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ENCHANTING EXPLORATION: AMBER AND THE KOMBOLOI TRADITION

THE EARTH’S TREASURES • MINERALS & JEWELRY

MAGNETITE An Iron Oxide That Changed the World GARNET FAMILY Spanning the Spectrum of Mineralogy

PETRIFIED WOOD Turn to Plant Anatomy to Understand

FOSSIL FINDS Beautiful Treasures Inside ‘Ugly’ Rocks

ROCK&GEM • Vol. 51 No. 7 • U.S. $5.99 Issue Code: 2021-07 • July 2021 Display until 7/20/2021 • Printed in the U.S.A.

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VOL. 51 NO. 7 • JULY 2021




VOL. 51 NO. 7 • JULY 2021

10 MAGNETITE An Iron Oxide That Changed the World

32 CHANNELING A MOTHER ROCK (Part II) Mineral Constituents of the Chert Complex

By Steve Voynick

By Rebecca Solon

16 WILDACRES REOPENS FOR FALL

40 THE GARNET FAMILY Spanning the Spectrum of Mineralogy

By Helen Serras-Herman

20 AMBER AND THE KOMBOLOI TRADITION Exploring the Science and Mindfulness Behind the Practice

By Bob Jones

54 STUDYING THE PAST OF PETRIFIED WOOD Trust Plant Anatomy to Be Your Guide When Working In the Present

By Helen Serras-Herman

By Doug Foster

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REGULAR COLUMNS Field Notes ..................................6 Bench Tips ................................18

64 TRAHEDRITETENNANTITE Unassuming, Handsome, and Confusing Minerals By Bob Jones

Fossil Finds ...............................28 The Road Report ......................46 Earth Science News..................52 Community Outlook ................. 62 Rock Science ...........................68 Sneak Peek: Glorious Gems ....70 Show Dates ...............................72 What to Cut ...............................74 On the Rock...............................76 Parting Shot...............................82

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CALL (855) 777-2325 © 2021 by Beckett Media, LLC. All rights reserved. Reproduction of any material from this issue in whole or in part is strictly prohibited. Single-copy price $5.99. Subscription in U.S.A. and possessions: 1 year (12 issues) for $29.95; 2 years for $52.95; 3 years for $74.95. Add $25.00 per year postage for Canada and all other foreign countries. EDITORIAL CONTACT INFORMATION: editor@rockngem.com

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On The Cover Magnetite photo: Cubic magnetite specimen from the Fowler Ore Body, Lawrence Co., New York (Heritage Auctions, www.ha.com); Amber photo: Baltic ambroid komboloi (Helen Serras-Herman); background Getty Images. Design by Shawn Stigsell

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FIELD NOTES our staff SNEAK PEEK AT ROCK & GEM’S 50TH COMMEMORATIVE ISSUE If you’ve subscribed to Rock & Gem for a while, you know we like to provide sneak peeks and teasers about forthcoming issues or specials or deals. We figured we’ve been talking about how to preorder a copy of RG50 (Rock & Gem 50th Commemorative) and the special perks that come with it. Yet, we also figure it may be interesting to know a bit about what you’ll find inside this limited-edition issue. With that, here’s a tiny sneak peek into the many things you’ll have the chance to enjoy when you purchase RG50: ■ A look back at the years since Rock & Gem came on the scene, courtesy of esteemed Senior Consulting Editor Bob Jones. ■ A celebration of another group celebrating 50 years in service — the Old Pueblo Lapidary Club, courtesy of Helen Serras-Herman. ■ A Rock & Gem Revisited adventure in Tick Canyon, and a 1971 digging excursion, courtesy of Lee Martin. ■ A profile introducing revered agate expert Eugene Mueller, owner of The Gem Shop, Inc., a business also celebrating 50 years in operation. ■ An exploration of the Maine Mineral & Gem Museum, a labor of love and perseverance that continues to defy the odds. ■ A Rock & Gem Revisited 1985 examination of The Great Fossil Trees of Arizona, courtesy of Bob Jones. ■ The unique and prolific partnership between the Austin Gem and Mineral Society and Nature’s Treasures of Texas. ■ A mini directory of museums to support your road trip planning efforts. ■ A handy guide to successfully photographing small geological specimens, courtesy of Richard Gross. ■ Reader stories about finding treasures, overcoming challenges, growing in knowledge and

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appreciation, and even finding love through rockhounding and lapidary. Again, this is just a sneak peek at some of the things you’ll find in RG50. If you want to know more and see what else awaits, we recommend you preorder your copy of RG50 today. The price is $9.99, and shipping to U.S. addresses is free when you order by July 13, 2021. The Rock & Gem 50th commemorative issue is scheduled to ship by the middle to the end of July 2021. To order, visit www.beckettmedia. com/rng-50th-anniversary OR call 855-777-2325.

GLORIOUS GEMSTONES ISSUE #2 AVAILABLE NOW The second issue of Rock & Gem’s printdigital hybrid series, Glorious Gemstones, is available for free access now. Among the topics featured in this second issue (of a three-issue series) include: tsavorite, mustvisit destinations to dig for gems, diamond fluorescence, gemstones that fared well at recent auctions, and profiles featuring sponsors Joseph P. Stachura Co., Inc., and Fazmagoric Treazures. To access Glorious Gemstones Issue #2 for free, visit www.rockngem.com/ digital-library.

EDITORIAL BOB JONES Senior Consulting Editor ANTOINETTE RAHN Managing Editor SHAWN STIGSELL Graphic Design JIM BRACE-THOMPSON MARC DAVIS RUSS KANIUTH BOB RUSH HELEN SERRAS-HERMAN STEVE VOYNICK Regular Contributors

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Minnesota’s banded-iron ore consists of alternating layers of hematitemagnetite and chert. WIKIMEDIA COMMONS

MAG NETITE

A NATURAL HISTORY An Iron Oxide that Changed the World STORY BY STEVE VOYNCIK

W

hether they will admit it or not, most placer miners have voiced unkind comments about magnetite. And that’s understandable, because magnetite is the primary component of the ubiquitous, heavy, black sands that often clog sluice box riffles. But there’s another side to magnetite that deserves respect, for this iron-oxide mineral has profoundly influenced history, culture, industry, and science. The best-known variety of magnetite is lodestone. Its natural magnetism has created colorful alchemistic lore; greatly advanced navigation, This magnetite-calcite specimen from Utah’s Iron Springs district shows typical octahedral form and triangular faces. STEVE VOYNICK

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surveying, and cartography; and inspired landmark breakthroughs in scientific thought. Magnetite made possible the early voice recorders that revolutionized radio broadcasting; today, it is used in many industrial dense-media-separation processes. And that’s not all. More than a half-billion tons of magnetite ore are currently mined worldwide each year as a source of iron. And geophysicists study magnetite grains in igneous rocks to learn about the ancient Earth’s magnetic fields and tectonic-plate movements. Magnetite (iron oxide, Fe3O4) consists by weight of 72.36 percent iron and 27.64 percent oxygen. It crystallizes in the isometric system, usually as octahedrons, occasionally as dodecahedrons, and rarely as cubes. Opaque and with a submetallic-to-metallic luster, magnetite is black to dark-gray in color with an occasional hint of blue iridescence. Brittle and with a subconchoidal-to-uneven fracture, it has a Mohs hardness of 5.5-6.5 and a substantial specific gravity of 5.17. Abundant and widely distributed, magnetite is present in most mineral environments. It occurs in particulate, crystalline, and massive forms and is a common accessory mineral in igneous, metamorphic, and sedimentary rocks. When magnetite weathers free from host rocks, its density enables it to concentrate gravitationally on beaches and in placer deposits.

PHYSICAL PROPERTIES Magnetite’s most notable physical property is its natural magnetism, which is by far the most intense of any natural material. One of nature’s basic forces, magnetism is produced when moving electrons generate electromagnetic fields characterized by the dipole effect of polarization. A familiar example of polarization is the north-south poles of bar magnets, in which like poles repel and opposite poles attract. The story of magnetite’s magnetic properties begins with iron. Because of its atomic structure, iron has the greatest magnetic susceptibility—the tendency to become magnetized—of any metal. Cobalt and nickel can also become magnetized, but not nearly to the extent that iron can. The magnetic susceptibility of a metal, mineral, or alloy is determined by the amount of iron, nickel, or cobalt present in it and the degree of atomic alignment that is possible within its structure. Many minerals exhibit trace magnetism, but few have any significant level of magnetic susceptibility. On the magnetic-susceptibility scale, nonmagnetic minerals are rated at zero. Magnetite, the only

This geologist is unable to hold a steel pen perpendicular to a massive vein of lodestone. UNITED STATES GEOLOGICAL SURVEY

mineral with obvious magnetism, is rated at 20. Next is chromite (iron chromium oxide, FeCr2O4), with a magnetic-susceptibility rating of 1.0. Because the iron in magnetite is present as both ferrous (Fe+2) and ferric (Fe+3) ions, magnetite can be better described as ferro-ferric oxide with the complete formula Fe+2Fe+32O4. Its crystal lattice consists of tightly packed cubes with oxygen ions occupying the corners and iron ions at the interstices (openings). The ferrous and ferric ions occupy fixed, precise tetrahedral and octahedral sites. This arrangement permits a continuous, directionally aligned flow of electrons between the ferrous and ferric ions. The resulting electrical vector generates a magnetic field just as a wire conducting an electrical current also creates a magnetic field. Magnetite’s directional vector and magnetic field keeps its iron ions in directional alignment, with each behaving as a tiny bar magnet to maintain its magnetism.

COMMON BEHAVIORS Although “normal” magnetite is attracted to magnets, it does not attract bits of steel (or other bits of magnetite). Only lodestone, the relatively rare variety of “automagnetized” magnetite, has sufficient magnetism to attract steel. The word “lodestone” stems from the obsolete word “lode,” which meant “course.” When lodestone appeared in Middle English in the early 1500s, it meant “leading stone” or “course stone,” alluding to its use in compasses.

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M AGN E T I T E : A NAT U R A L H IS TORY

This three-inch lodestone specimen is from Utah’s Iron Springs district. STEVE VOYNICK

Not all magnetite can become lodestone. In order to magnetize, it must have a specific composition and structure. Unlike normal magnetite, lodestone contains traces of maghemite (cubic iron oxide, Fe2O3, a hematite polymorph) and ions of titanium, aluminum, and manganese. These impurities create an inhomogeneous structure that increases lodestone’s magnetic force and makes it a permanent magnet. The Earth’s magnetic field is not strong enough to magnetize magnetite; the leading theory of how lodestone becomes magnetized focuses on lightning strikes. Lightning is an instantaneous and massive discharge of electrons that generates a very brief, but extraordinarily intense, local magnetic field. Upon striking a magnetite deposit, lightning’s magnetic field forces magnetite’s iron ions into more perfect alignment to increase its magnetism. Lodestone’s occurrence at or near the surface and not at depth supports the theory of lightning as the origin of its magnetism. Two criteria distinguish lodestone from normal magnetite. Unlike normal magnetite, lodestone attracts and holds bits of steel, and it exhibits a distinct polarity that is detectable with a compass.

ANCIENT-AGE AWARENESS

Sand dunes at Colorado’s Great Sand Dunes National Park contain significant quantities of magnetite sand. STEVE VOYNICK

Awareness of lodestone’s magnetism seems to have evolved independently in Greece, China, and Mesoamerica. The Roman scholar and naturalist Pliny the Elder attributed the discovery of magnetism to Magnes, a shepherd in Magnesia, Asia Minor (now western Turkey). Magnes, who preceded Pliny by several centuries and was likely a mythical figure, supposedly discovered magnetism when lodestone attracted the iron nails of his shoes. Historians place the greater significance of Pliny’s writing in the fact that Magnesia became the etymological base of the

The bottom of Medano Creek at Colorado’s Great Sand Dunes National Park has prominent flow patterns of dark magnetite sand.

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STEVE VOYNICK


M AGN E T I T E : A NAT U R A L H IS TORY By 1300, Europeans were utilizing “dry” compasses with magnetized steel needles balanced on pivots. By the dawn of Age of Exploration around 1400, dry magnetic compasses were routinely used for navigation and cartography. By then, mariners also understood the deviation between magnetic and astronomical north, and German miners were using compasses for underground surveying.

DEBATING LODESTONE MAGNETISM

Lodestone’s magnetism led directly to the invention of one of the world’s most useful instruments—the compass. STEVE VOYNICK

English word “magnet” in the 1400s, and of the related words “magnetic” and “magnetism” in the early 1600s. The phenomenon of magnetism is mentioned in Chinese texts as early as 1800 BCE. By 200 BCE, these texts frequently described in great detail the ironlodestone attraction. Although lodestone was not yet being used for navigation, Chinese geomancers did fashion it into “south-pointing spoons” for divination purposes. Balanced on polished bronze plates, these lodestone spoons aligned themselves along a northsouth axis to aid the feng shui practice of arranging living spaces in harmony with the spiritual forces present in the environment. Archaeological evidence suggests that some ancient Mesoamerican cultures also knew of magnetism. About 600 BCE, the Monte Alto culture in what is now Guatemala sculpted large pot bellied figures and human heads from magnetite-rich basalt. Archaeologists have detected strong magnetism in these sculptures—always at the navel and face sections. Researchers suggest that Monte Alto stoneworkers used lodestone to orient the sculptures for magnetism-related ceremonial or spiritual purposes. Another magnetism-related artifact is an Olmec lodestone bar dating to 200 BCE that may have aided in the orientation of temples, dwellings, and graves. Chinese mariners were using lodestone compasses for navigation by 700 CE. And by 850 CE, after learning to magnetize steel by rubbing it on lodestone, they had invented “wet” compasses with magnetized steel needles that floated on water. Europeans began making wet, steel-needle compasses around 1190.

Meanwhile, alchemists continued to debate the cause of lodestone’s magnetism. According to one theory, lodestone emitted an invisible effluent that created a void into which bits of steel would rush. Another theory proposed that garlic and diamonds could negate lodestone’s magnetism. Many alchemists also believed that lodestone possessed a soul, intelligence, and healing properties that cured everything from gout to distemper. Others simply condemned magnetism as a machination of the devil. Rare and mysterious, lodestone was costly and much in demand by those who could afford it. Among the notable figures of the 15th and 16th centuries who possessed lodestone specimens was the English scientist Sir Isaac Newton, whose gold ring was set with a lodestone fragment that could pick up many times its own weight in steel.

This six-ounce armed lodestone, owned by Galileo Galilei in the late 1500s, can lift 15 pounds of steel. WIKIMEDIA COMMONS

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M AGN E T I T E : A NAT U R A L H IS TORY by such names as “magnet ore,” “black iron ore,” “Magnetstein” (magnetic stone), and “Magneteisenstein” (magnetic iron stone). In 1854, Austrian chemist Wilhelm Karl von Haidinger formally assigned it the name “magnetite.” Magnetite was among the first minerals analyzed by X-ray diffraction in 1915. Knowledge of its atomic structure and ferro-ferric composition, along with a basic understanding of the emerging field of particle physics, finally combined to explain magnetite’s magnetism. Magnetite and hematite (ferric oxide, Fe2O3) are the primary ores of iron. The 2.6 billion metric tons of ore now mined worldwide each year include 800 million metric tons of magnetite ore.

MAGNETIC MINNESOTA

The sedimentary, hematite-magnetite iron deposits of northeastern Minnesota were laid down about two billion years ago during the Great Oxygenation Event. WIKIMEDIA COMMONS

Especially popular among the elite was “armed” lodestone—pieces of lodestone fixed with iron caps on the pole ends that concentrated the magnetic force. The six-ounce, armed lodestone of Italian astronomer and physicist Galileo Galilei could lift 15 pounds of steel. Galileo bestowed armed-lodestone gifts upon many prestigious individuals, including Holy Roman Emperor Ferdinand II and the wealthy Duke of Tuscany and patron of the arts Ferdinand de’ Medici. England’s Queen Anne (reigned 1702-1714) used a lodestone set into an engraved silver case in her “royal-touch” healing ceremonies that supposedly cured the “king’s evil” (scrofula). Anne refused to touch her afflicted subjects directly, “treating” them instead from a distance with the magnetic force of her armed lodestone. Lodestone also inspired groundbreaking scientific thought. In 1600, English physician and physicist William Gilbert published De Magnete, a landmark work about magnetism in which he correctly deduced that, like lodestone, the Earth itself was a magnet with north-south magnetic poles. In the late 1600s, the Royal Society of London displayed a six-inch-diameter lodestone sphere to demonstrate the Earth’s magnetic field. Lodestone remained the sole source of magnetism until 1819, when Danish physicist Hans Christian Øersted discovered that wire conducting electrical current also generated magnetic fields. For centuries, magnetic iron oxide had been known

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Among the Earth’s oldest ores are northeastern Minnesota’s huge banded-iron deposits that consist of both hematite and magnetite. Banded-iron ores are partially altered sedimentary rock that was laid down during the late Precambrian Era. At that time, the Earth’s atmosphere was deficient in oxygen, and what is now northeastern Minnesota was covered by a warm, highly acidic sea rich in dissolved iron and silica. Some 2.5 billion years ago, the Earth’s atmosphere began changing with the onset of the Great Oxygenation Event. This major biochemical transition lasted one billion years and was triggered by the rapid growth of cyanobacteria, simple, algae-like life forms that obtain energy from photosynthesis and release large volumes of oxygen. As seawater slowly became oxygenated, it lost its acidity and precipitated iron and silicon. The iron, in the form of magnetite, and silicon, in the form of chert (microcrystalline quartz), accumulated in alternating layers on the sea bottoms. The heat and pressure of deep burial eventually lithified these sediments into hard, durable rock. Meteoric water and hydrothermal fluids later oxidized much of this magnetite into hematite. The magnetite portion of the Minnesota bandediron ores proved both a blessing and a curse. Geologists could map the Minnesota deposits using only compasses to detect local variations in magnetic declination caused by magnetite concentrations. Magnetite was the preferred ore because it was richer in iron than the hematite ore and could be inexpensively concentrated by magnetic separation. But on the downside, the large bulk cargoes of concentrated magnetite ore turned Great Lakes ore


M AGN E T I T E : A NAT U R A L H IS TORY ships into giant magnets, each surrounded by its own intense magnetic field that made compass navigation impossible. Until the introduction of global-positioning-satellite navigation systems, shipping magnetite ores on the Great Lakes was a hazardous undertaking.

and intensity of the Earth’s magnetic field that existed at that time. Paleomagnetic data enable geophysicists to determine the magnetic-pole proximity of the orientation of tectonic plates over hundreds of millions of years. This data also helps understand the “geodynamo”—the MAGNETITE IN MODERN USES circulating currents of molten core material that generIn the early 20th century, finely powdered magnetite ate the Earth’s magnetic field. Finally, paleomagnetic made possible the development of quality voice record- data are a record of the Earth’s magnetic-pole reverers. The first voice recorders in the 1890s utilized thin, sals—north-south “flips” that have occurred in the past steel wire as a recording medium but had poor voice and will occur again in the future. reproduction. In 1928, German scientists designed As placer miners know, magnetite is abundant and voice recorders with magnetite microparticles loosely widely distributed. Some “black-sand” ocean beaches impregnated in plastic tape. consist largely of magnetite As this tape moved through a and have been mined for iron recording “head,” a magnetic in the past. Two particularly Britain’s Queen Anne interesting magnetite sites are in field governed by electrical sound signatures aligned the used this silver-encased south-central Colorado’s Great Sand Dunes National Park and magnetite particles in specific armed lodestone in southern Utah’s Iron Springs patterns. A playing head then healing ceremonies Mining District. detected the tape’s magnetic in the early 1700s. field and amplified the electrical At Great Sand Dunes, streaks signal for quality reproduction of dark magnetite appear of the original voice. below the crest of each dune Previously, all radio programs where wind has gravitationally were, by necessity, broadcast separated the magnetite from “live.” Magnetite-based voicethe lighter-colored quartz sand. recording tape revolutionized The sandy bottom of the park’s radio broadcasting by enabling broad, shallow Medano Creek is programs to be rebroadcast and also heavily streaked with flow patterns of dark magnetite sand. archived. In the 1940s, powdered Mormon immigrants first mined the Iron Springs Mining magnetite was put to work in WIKIMEDIA COMMONS industrial dense-media-separaDistrict west of Cedar City, Utah, tion processes to “clean” pyrite-rich, high-sulfur coal. for iron in 1852. In many of the district drainages, black Crushed coal floated on density-controlled, powdered- magnetite crystals contrast with the lighter-colored magnetite water slurries, while the troublesome pyrite gravels and are readily identified by their high density and reflective, triangular crystal faces. Some Iron and other gangue materials sank as waste. Today, magnetite-based, dense-media-separation is Springs magnetite specimens are lodestone that exhibit used in several mineral-beneficiating processes and, distinct polarity and attract steel objects like paper clips. most importantly, in separating mixed, recycled metals. The specimens of massive magnetite available at Because of their magnetism, magnetite particles in the rock shops and online sites are often labeled “lodestone”—but few are natural lodestone. Most have had slurries can be easily recovered and cleaned for reuse. In the 1960s, magnetite particles present in igneous their magnetic intensity artificially enhanced by contact rocks became the basis of the study of paleomagnetism, with strong magnets. a subscience of geophysics that deals with ancient Well-developed octahedrons and natural magnetism magnetic fields. While originally contained in viscous have long made magnetite a favorite among mineral magma, these magnetite particles aligned with the collectors. And even placer miners might agree that Earth’s magnetic field like tiny compass needles. When knowing a little about magnetite’s remarkable history the magma solidified, the magnetite particles “froze” makes those riffle-clogging black sands a little easier in place, creating a permanent record of the direction to take.

FU N FAC T

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PICKS & PANS

BY HELEN SERRAS-HERMAN

The Return of Fall 2021 Wildacres Workshop

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e are very excited that after more than a year of canceling three EFLMS Wildacres Workshops due to COVID-19, finally the EFLMS Wildacres Workshop will be back this fall. It will be held September 6-12, 2021. The Wildacres Workshop takes place in the beautiful mountains of North Carolina, near Asheville. The workshop is sponsored by the Eastern Federation of Mineralogical Lapidary Societies. For information and registration, please visit www.efmls. org/wildacres. Besides the hands-on workshops, at every session a Speaker-in-Residence gives six lecture presentations. As the coordinator for the speakers, I am very happy to share that this fall the Speaker-in-Residence will be Wolfgang Mueller. Wolfgang is a retired geologist, mineral collector, and a very active lapidary. He has rockhounded in many places around the country and is famous for his hand-cut spheres and eggs, as well as rare gem material cabochons and one-of-a-kind beads. His talks range from mineral collecting to lapidary. He has a wealth of knowledge, which he is always happy to share. He received a top prize best-of-class award at the 2019 Tucson Gem & Mineral Show for his self-collected wulfenite specimen exhibited in a in a competitive case exhibit. Wolfgang was born in 1942 in the same town (Belgrade) as the person for whom Wulfenite is named – Franz Wulfen, a Jesuit born in 1725. He has a Bachelors and Masters degree in geology from the University of California in Riverside. He worked at Magma Copper in San Manuel and their corporate entity, Newmont Exploration, in Danbury, Connecticut. Wolfgang moved back to Arizona, to Oracle, some 22 years ago and loves going out rockhounding and collecting minerals. He can still swing a 20lb sledgehammer! Wolfgang will be accompanied at Wildacres by his wife, Diana, who is also a lapidary and jewelry artist. Together, they are the lapidary and jewelry forces behind their company DiWolf, exhibiting at several gem & mineral shows (www.diwolf.com). My Road Report article, “Visiting with DiWolf,” appeared in the August 2020 R&G magazine. Also, 2018 Lapidary Hall of Fame inductee Bernie Emery will be teaching the cabochon class. You can read my Road Report article about this great teacher, “Hall of Famer Bernie Emery,” in the May 2020 R&G magazine. For a detailed story about the Wildacres Retreat and Workshop, you can read my article in the April 2019 issue of Rock & Gem magazine.

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Bernie Emery, cabochon class teacher.

Wolfgang Muller, speaker-in-residence.


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BENCHTIPS

BY BOB RUSH

Creating A Decorative Feature

T

his column outlines a step-by-step project to create a decorative feature on the back of your cabochons using small burrs that mount in a flex shaft. It involves using diamond ball burrs of various grits and homemade wood burrs. The first step is to select a translucent area on your cab or slab that shows considerable transmission of light and color in the place where you will make the decorative feature. Mark a point with a felt tip pen and start the hole with a small coarse grit 1/8-inch diamond bur. I do the carving in a shallow plastic bowl cut from the bottom of a large plastic bottle with ½-inch of water inside. Dip the piece in the water and grind with the burrs for a few seconds and dip again. Using a ½-inch diameter coarse burr, continue the grinding by holding the side of the bit in the previously made hole. Continue dipping and grinding for a few seconds. Every few minutes, turn the burr vertically and correct the shape of the hole because when you grind with the side of the burr, it pulls slightly sideways. Ball burrs do not grind very well if you hold them vertically. As you are grinding the hole, stop and look at the back of the piece under a strong light to see how it appears. If you like how it looks, begin the sanding steps to remove the grinding marks. Shape some 1/2-inch diameter 1/2-inch long wood dowel pieces to match the hole size on the piece. Cut the dowel into ½-inch long pieces. Locate the center end of the dowel piece and drill a small hole into the end using a 1.5mm drill bit. Mount the dowel piece on the screw mandrel and shape it with a coarse file while spinning it in your flex shaft handpiece. Check it frequently for the correct shape to match the hole in the agate piece.

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Bench Tips

1. Locate and start the hole with the small bit. 2. Thread the mandrel into the wood dowel. 3. Shape the dowel with a coarse file. 4. Place a small amount of grit into the hole. 5. Push the wood bur firmly into the grit. 6. Polish with Cerium Oxide. 7. The finished piece.

Make two more just like it. You will need three of these, one for the 220 grit, one for the 400 grit, and one for the polish step. For the first sanding step, use 220-grit tumbling media. Mix the grit in a small, shallow condiment cup with a small wooden spatula and water to make a thick slurry. Add only enough water to make the slurry about the consistency of toothpaste. Using the spatula, scoop some of this slurry into the hole on your piece. Wet the wood bur and push it into the hole rather firmly to embed the grit into the wood. Run the flex shaft unit slowly and move the wood bit around a lot, including the hole’s sides. Stop and add more slurry when the wood bit starts squeaking. Repeat this process a few times. Stop and wash out the slurry and check for how well the sanding has removed the grinding scratches. The hole should start to look somewhat shiny. Repeat this step with a new wood bit dipped into water and the 400-grit media. The hole should be even shinier after this step. Wash everything very thoroughly and do the same process with a cerium oxide slurry. You should get a very well-polished hole after a few minutes.

SUPPLY GUIDE I get the diamond bur sets from Jadecarver. com. They come in a graduated 14 piece set and six different grits. The screw point mandrels have a ½-inch length thread, and the shank diameter is 1/8 inch. They can be found at Rio Grande Supply. Bob Rush has worked in lapidary since 1958 and metal work and jewelry since 1972.He teaches at clubs and Modesto Junior College. Contact him at rocksbob@ sbcglobal.net.

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I was truly impressed with this amber necklace from Messenia, Greece (15th c. BC), exhibited at the National Archeological Museum in Athens.

Amber and the Komboloi Tradition Exploring the Science and Mindfulness Behind the Practice STORY AND MOST PHOTOS BY HELEN SERRAS-HERMAN

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A

The Venetian castle of Palamidi, built under the Venetian rule from 1685 to 1715, looms majestic over the historic town of Nafplio, in Greece.

34-38 million year old (ma) and contains a significant amount of succinic acid (3-8%) compared to other ambers, which contain none or very little”. Pedersen also said, “Amber from the Dominican Republic is between 16 and 20 ma, and so is Mexican amber, while amber from Burma (known as burmite) is known to be over 100 million years old. Burmite is a little harder than other ambers and is often cracked, with calcite inclusions. Petersen discusses all ambers on her website (www.maggiecp. com) and those from “historic” locations, including North America, France, Lebanon, Romania, and Sicily, and the most recent finds from Australia and Ethiopia. I asked gemologist, appraiser, and lecturer – and my good friend- Denise Nelson, from the Inner Circle, to share her experience from her recent visit to the Amber Museum – the Bursztyne Museum - in Gdansk, Poland, dedicated to the history of amber. “The museum is

GETTY IMAGES

mber is an organic material, a plant resin originating from coniferous trees, which lived between 320 and 60 million years ago. The oldest recovered amber dates to the Upper Carboniferous period, 320 million years ago (www.mindat.org). Over thousands of years, the soft resin became a hard, fossilized resin, and the molecules have polymerized. The conditions of heat, pressure, oxygen and light exposure must be right for the amber to form. Its chemical composition is approximately C10H16O. Amber’s structure is non-crystalline. It may show flow lines, and often have inclusions of exquisitely preserved organisms, such as insects, spiders, frogs and lizards, bird feathers, bones, and plant materials, which were trapped in the tree’s resin. Amber is found in several places worldwide, but amber from northern Europe collected around the Baltic Sea shores is considered the best quality. Amber is found on the west coast of Koenigsberg in Prussia, which became Kaliningrad of Russia. Amber is also found in Burma, Sicily, Central Europe, Romania, Mexico, Canada, several US locations, and the Dominican Republic (Amber, The Golden Gem of the Ages, Patty C. Rice, 1980). Baltic amber has a distinct “fingerprint” inclusion - plant hairs (stellate trichomes) - not found in the Dominican amber. Although ambers from different countries are equally labeled “amber,” there are differences between the materials based on their age, tree origin, and chemical composition, all of which reflect on the quality. I reached out to Maggie Campbell Pedersen, expert gemologist from London and author on organic gem materials, who shared with me her latest data on dating amber: “the coniferous-origin Baltic Sea amber is

Various amber and imitations from our collection: Natural amber (front left), copal (middle), ambroid (right), glass (back left), sun-spangled amber drops, and amber imitations (front right) – Bakelite, plastic, African glass, water buffalo horn.

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A MBE R A ND THE KOMBOLOI TR A DITION

Baltic amber necklaces from my personal collection

We had the pleasure to meet collector and researcher Aris Evangelinos, who established the Komboloi Museum in 1998.

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A MBE R A ND THE KOMBOLOI TR A DITION

Available Now

Amber from northern Europe collected around the Baltic Sea shores is considered the best quality.

housed in a medieval seven-floor high tower rebuilt after the WWII destruction in the center of the city. Every floor holds amber collections from different periods. The exhibits, which include the most astonishing ancient plants, animals, and insects encased in amber, thick-skinned amber boulders, and modern art created by local artists, surprise and captivate visitors. Hundreds of natural Baltic amber items, placed in well-lit cases inside the domed dark rooms which once housed a torture chamber and a prison, create a golden glow.” Denise also said, “The local streets, filled with tourist shops selling an abundance of amber items, are in stark contrast to the cold and harsh waters of the Baltic Sea, where the ancient forests once stood and amber has been washed up, collected, traded, and treasured since the Paleolithic era.” The magnificent Amber Room was a chamber decorated with amber panels in the Catherine Palace near St. Petersburg, Russia. It was initially constructed in the early 18th century, but it was dismantled by the German Nazis and disappeared during World War II. An astonishing reconstruction of those panels and that room began in 1976 and was finished and installed in 2003. During the 2004 Tucson gem shows, we visited the JOGS Amber Pavilion and the

Amber can be cut and carved with simple steel tools, such as saws, files and knives. This “Amber Queen” is one of my early carvings.

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A MBE R A ND THE KOMBOLOI TR A DITION magnificent Amber Room Museum exhibit with real Amber Room objects and carvings from Russia. I talked to the amber workshop director, Boris Igdalov, who was on site demonstrating. I was fascinated by the craftsmanship perfection of the amber mosaic pieces. Among them a chalice, a plate with the Romanov seal, and fabulous chess set with chess pieces of transparent amber and opaque amber. Amber was known in the ancient Greek world as electron. It was described in Homer’s Odyssey, and later by the ancient Greek historians Theophrastos and Hesiod, and philosopher Aristotle. Amber was considered an amulet against the evil eye, and a therapeutic against aches of the neck and tonsils. My husband and I saw fabulous amber necklaces at the National Archeological Museum in Athens, Greece, from the Mycenaean civilization, dating to the 15th and 16th centuries BC. Amber’s hardness is between Mohs 2.0 and 2.5, specific gravity is 1.08 (it floats in a robust salt solution), and refractive index is 1.54. Colors include golden, yellow to orange to brown, pale lemon yellow, reddish, whitish, and, rarely, greenish or bluish. Amber ranges from transparent to subtranslucent to opaque, which is known as “bastard amber.” Amber can be cut and carved with simple steel tools, such as saws, files and knives. Sanding can be done with sandpaper in various grits – from coarse to fine- preferably with water to avoid heating. Amber can be polished with flannel, felt, or flexible leather impregnated with tripoli powder or tin oxide (Gem Cutting, A Lapidary Manual, John Sinkankas, 1955, 1962).

YOUNG FOSSIL RESINS AND AMBER TREATMENTS Copal is a fossil resin similar to amber but much younger (2.58 Mya-1760 AD, A Revised Definition of Copal, www. nature.com, Scientific Reports, Nov 2020), and therefore not as hard. It is often sold as copal-amber to confuse buyers. Copal tends to craze easier than amber. Copal comes from Central America, Colombia, Dominican Republic, Madagascar, and New Zealand. One of the methods in identifying true amber is to touch it with a hot needle. Amber produces a strong, distinctive balsamic odor due to its coniferous origin, but so does copal. There are several natural amber treatments. One is known as “clarification,” under which amber is heated in vegetable oil to become more transparent. During that process, circular disc-like cracks, known as “lily pads,” may occur. Sometimes these inclusions are induced deliberately, and the amber is known as “sun-spangled.” As reddish amber is rare, dyeing amber to a reddish coloration or oxidizing the surface by heating is another practice. Another type of treated amber is pressed amber, also known as reconstituted amber or ambroid. Small amber pieces are bonded together

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This amazing amber mosaic chalice was on exhibit at the 2004 Tucson gem show.

This amber mosaic featuring both transparent and opaque amber was on exhibit at the 2004 Tucson gem show.

under heat and pressure to form larger blocks. There are several glass and plastic imitations on the market, but most are easily distinguished from amber. The majority of them are heavier (have higher specific gravity) than amber; hence, while amber floats in strong salt solutions, most plastics will sink, and glass is colder to the touch. Visit Pedersen’s website www.maggiecp.com and the chapters “Treatments and Enhancements of Baltic Amber,” “Red Ambers,” and “Green Ambers” for her in-depth research, an extensive list of treated ambers, and tests about how to identify them.

THE GREEK KOMBOLOI TRADITION Known as worry beads in the West and komboloi in Greece, the komboloi is a hand-crafted item with beads on a string in an odd number, with a merging end piece, and


A MBE R A ND THE KOMBOLOI TR A DITION

Amber boulders collected at the Baltic Sea shores may be covered by thick skin, such as this one on exhibit at the Amber Museum. DENISE NELSON

a tassel. The komboloi (plural komboloia) is normally held – or played -in one hand, and it is either twirled around the fingers, or the holder moves the beads one or two at a time up and down the string. The word komboloi is a compound word derived from the Greek words kombos, (=knot), and the verb leo, which means “to say” in Greek. Although the komboloi has a seeming similarity to prayer beads used in many world religious traditions, the Greek komboloia have no religious function, contrary to Muslim prayer beads, which must have 99 beads for the 99 prayers, and the Hindu prayer beads that have 108 beads. The komboloi came into the Greek culture during the 19th century, after the end of the 400-year Turkish occupation and Greece’s independence in 1821. The Greek komboloi’s purpose is purely to pass the time and relax, for moments of leisure and solitude, among

friends or in loneliness to relieve the aches of a broken heart. Fondling each bead and the beads’ rhythmic falling contribute to a relaxing meditation. Komboloia were used mostly by older men, often sitting at coffee shops and wine taverns, playing cards and tavli (backgammon) – traditional, iconic scenes from mid-20th century movies and photos. From men within the underprivileged, the underground, and poor, the komboloi has transcended every class and gender. The komboloi tradition continues today as collectible and decorative items. Souvenir and antique shops all over Greece are filled with komboloia hanging on walls and racks, ranging in size, materials, and prices, from small, inexpensive plastic beads to large gemstone or glass beads, to authentic antique pieces. The old-timers used to rub the amber komboloi to release its aromatic smell, thus making

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A MBE R A ND THE KOMBOLOI TR A DITION

During the 2004 Tucson gem shows, we visited the magnificent Amber Room Museum exhibit with real Amber Room objects and carvings from Russia.

smell an important component of the komboloi’s value. The traditional material used for komboloia is natural amber for the most expensive examples and amber resin that has been reconstituted for somewhat less expensive. Natural coral, especially black coral, camel bone, mother-of-pearl, and ivory was also used. Being warm to the touch, organic materials are considered more pleasant to handle than nonorganic materials, including minerals, plastics, and metals. To traditionalists and purists, contemporary materials besides the organic materials are considered sacrilege and wretched imitations (Aris Evangelinos, The Komboloi and its History, Komboloi Museum Publications, 2000). Personally, I enjoy komboloia of all types and materials, and have brought back from Greece many as gifts for my family and friends.

two palm widths. Longer komboloia, especially collectible ones, are about 13 inches plus the length of the empty cord. The Greek komboloia have an empty cord portion for the beads to move freely up and down. Silk cord is considered the best thread, although some contemporary komboloia include chain instead, another sacrilege to purists. The preferred bead shapes are tube, round, oval, and sometimes squarish or carved. At the end of the strand, a much larger fixed bead called the “priest” symbolizes power and strength; it may be simple or elaborate, usually tapered. Another bead called the “shield” separates the two threads and helps the beads flow freely. The komboloi is always finished with a tassel.

THE KOMBOLOI MUSEUM - UNIQUE IN THE WORLD THE KOMBOLOI COMPONENTS The Greek komboloi, free from religious restrictions, flourished during the past one hundred years. Generally, the komboloia contain an odd number of beads, often 15, 17, 19, or 21. The odd number is regarded as ideal for optic balance. The most common komboloi length is around ten inches,

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The Komboloi Museum is totally devoted to the art and history of the komboloi. It is located in the historic town of Nafplio (Nafplion or Nauplio), the sea-port town on eastern Peloponesse, Greece, about a two-hour drive from Athens. The Venetian castle of Palamidi (built under Venetian rule from 1685 to 1715) looms majestically over


A MBE R A ND THE KOMBOLOI TR A DITION

The Komboloi Museum, located in the historic town of Nafplio, is a totally unique museum in the world, devoted to the art and history of the komboloi.

the town of Nafplio. The town later became the capital of the first Hellenic Republic from the start of the Greek Revolution in 1821 until 1834. The Komboloi Museum was a wonderful surprise when my husband and I visited the area. After visiting the Nafplio Archeological Museum, we walked across the beautiful large plaza, and came across the Komboloi Museum. The Komboloi Museum was established in 1998 by collector and researcher Aris Evangelinos and his wife, Rallou. The museum aims to save and spread the knowledge of the traditional Greek komboloi. The museum is housed in a privately-owned two-story neoclassical-style building and operates under the supervision of the Ministry of Culture. The exhibition halls are located on the upper floor, while a workshop and retail shop occupy the ground floor. The museum’s extensive collections, workshop and shop make it totally unique in the world. Mr. Evangelinos studied and collected komboloia since 1958, following the footsteps of his grandfather who had lived in Alexandria, Egypt, and had come across the komboloi trade there. The couple’s komboloi collection includes almost 1,000 strings

of beads from different cultures, dating from 1550 to 1950 AD acquired on their travels in Egypt, Syria, Turkey, Iran, Tibet, India and other places. The komboloia are made of natural amber, reconstituted amber, red coral, black coral (yusuri), bone, ivory, horn, and ebony. Over 360 pieces are on display in four halls, divided into Hinduistic, Buddhist, Muslim prayer beads, Catholic and Monastery rosaries, and the Greek strings of beads. Mr. Evangelinos talked to us about faturan – a type of reconstituted amber used for komboloia in Egypt. The original formula, mostly unknown today, was discovered by a Kuwaiti chemist, an Arab scientist named Faturan. He supposedly melted down natural amber leftover fillings from carved beads, and mixed them with Bakelite phenolic resin to mold individual beads. Color was enhanced by dipping in red wine or cognac and natural vegetable dyes, and then heated in the oven. The last genuine faturan beads were made in the 1940s. For the connoisseurs, there is even a difference between the original Egyptian faturan and the Persian faturan produced later, which has a different color and contains more Bakelite. Genuine faturan komboloi beads, most being 60 to 120 years old, are highly collectible and extremely expensive. Today, however, there are several faturan imitations causing confusion in the market. At the museum’s workshop, the owners conserve old strings of beads - often customers’ family heirlooms. Visitors can watch the fabrication of komboloia with the owners’ favorite handmade beads. In the gift shop, visitors can purchase authentic komboloia, replicas produced onsite, and new styles. We were very lucky that Mr. Evangelinos was present during our visit, and had the opportunity to listen to his stories, sign our copy of his book, and help us choose a special Baltic ambroid komboloi to treasure back home. Sadly, he passed away four years ago, as his daughter, Eleni Evangelinou, shared with me recently on a phone conversation. Eleni Evangelinou has taken over much of the museum’s operations and daily tours and continues the komboloi tradition. Ms. Evangelinou pointed out the importance of variations within ambers that result in different quality komboloia, and differences among faturan and mastic komboloia.

IF YOU GO The Komboloi Museum is located within Nafplio’s Old Town, at 25 Staikopoulou Street. The museum’s richly illustrated website www.komboloi.gr has information, komboloia for sale, and their two publications – including the newest, Amber….the Tears of Apollo. This area, rich in history, with many archeological sites and museums, is a top visiting destination.

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FOSSIL FINDS

BY PALEO JOE

Ugly Rocks Can Contain Beautiful Treasures

F

rom the outward appearance of certain ironstone or siderite nodules, they might seem to be ugly-looking dirty rocks, but they often hide beautiful treasures inside. Siderite or ironstone concretions from the area called Mazonia near Braidville, Illinois, often contain a rich diversity of plants...and animals. These plants and creatures once lived in the subtropical jungles, swamps, deltas, and forests in the Illinois Basin of Eastern Central Illinois. The area around Mazonia is known as a Lagerstatte (in German), which loosely trans-

lated means “resting place.” To paleontologists and scientists, it is an area with spectacular preservation of the flora and fauna of an ecosystem. The Mazon Creek flora and fauna from the Pennsylvanian Sub-Period, also called the Age of Plants, are some of the best known and most highly prized fossils. The Pennsylvanian lasted from some 323.2 million years ago to 298.9 million years ago. During this time, the area contained swamps filled with scale trees, seed ferns, true ferns, horsetails, the first emergence of conifers, and other ground plants. One can imagine these hot, steamy

An example of molted shrimp. ALL PHOTOS COURTESY OF THE KCHODL COLLECTION, THE PRIVATE COLLECTION OF PALEOJOE.

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Fossil finds

Part of Paleojoe’s Mazon creek fossil plant collection.

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Fossil finds

Example of an Essexella jellyfish.

A Mazon Creek fossil fern nodule.

jungles were filled with large ferns and primitive plants. The swamps were full of life scurrying and swimming about. As plants fall onto the rich soil or into the water, they are quickly buried. The process that formed siderite nodules began with decomposition of the plant and animal remains that produced carbon dioxide (CO2) that mixed with the iron in solution from iron-rich groundwater. The subsequent lithification, which is the compaction of sediment thus creating rock, caused the sediments to form protective nodules of ironstone around the plant and animal remains. The siderite or ironstone is an iron compound with a Mohs scale hardness of 3.75 - 4.25 and is a mineral that is composed of iron carbonate (FeCO3). These nodules are found in the remains of the open-

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pit coal mining operations that took place during the last century. They are quite common in the dirt and overburden that was removed in order to reach the rich coal veins. It is within these piles of dirt and sediment our search begins. Surface collecting, one can find these nodules; however, the best fossils are found within these piles and soft shale outcroppings. This is not the only area where fossilized plant material can be found, but it is one of the most well known. Other states include West Virginia, Pennsylvania, and Western Indiana, just to name a few. Often the nodules are hard and must be carefully broken open with a hammer. However, the freeze/thaw method is also utilized and recommended. The freeze/thaw is just what it describes: soak the nodules in water, place them in the freezer, remove, and thaw. If not broken, open, then repeat the process up to 15 or so times. If they still have not broken, it is time to smack them with a hammer. The concept is that the water will infiltrate the nodule and settle along the plane of the plant or leaf. When frozen, the water will expand and, as it freezes, it cracks the nodule along that horizontal plane. Plants and even animals such as clams, jellyfish, shrimp, insects, worms, horseshoe carbs, and crustaceans can be found. The highly prized and quite famous Illinois State Fossil, the exceedingly rare Tullymonster (Tullimonstrum), can also be found. But the highest occurrence of fossils in the area are ferns. Mazonia State Park is one area where the public is invited to come in search of these treasures. There are rules involved, and it is best to check the DNR website for up-to-date rules and regulations, but briefly: • There is a daily limit of one five-gallon bucket per person of nodules - that’s a lot. • Fossils found will not be commercially sold. • Must obtain a permit, and it must be available to be viewed by park personnel. • Fossil collecting only March 1 to September 30. But again, for more information, contact MazoniaBraidwood SFWA staff, P.O. Box 126, Braceville, IL 60407; call (815) 237-0063; or visit online: www.dnr.illinois.gov/Parks. And above all, go forth and enjoy what paleontological treasures nature can provide. Joseph J. “PaleoJoe” Kchodl is an award-winning paleontologist, author, storyteller, collector, a revered expert on the topic of trilobites, highly-sought-after presenter of school programs about fossils, keynote speaker and lecturer, and a global ambassador promoting digging and the appreciation of fossils. More can be learned by visiting his website: www.paleojoe.com.


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(PART II)

CH A N N E LI NG A

M O T H E R RO C K

Picasso Chert from Burro Creek, AZ, collected by Arizona State University Geology Professor and Author Stan Celestian.

Mineral Constituents of the Chert Complex STORY AND PHOTOS BY REBECCA SOLON 32 ROCK&GEM | WWW.ROCKNGEM.COM


n the March 2020 issue of Rock & Gem, in my article entitled Cherishing Chert: A Mother Rock for the Ages, I discussed the ancient origins of chert as a building block of Earth’s early ocean basins. I illustrated my narrative with two famous formations, the Kaibab Cliffs of the Colorado Plateau and the banded iron formations (BIFs) of Mingus Mountain in the Black Hills region of north-central Arizona. These ancient deposits crop out at the top of Mingus Mountain and are the source of the hematite and jasp-chert BIFs of the Verde Valley. Chert is a name that is often used interchangeably with another impure opaque variant of chalcedony known as jasper thus the use of the term “JaspChert.” The unique rocks described in this article combine distinguishing characteristics of both varieties and constitute minerals of the chert complex.

I

CHERT-BASED MINERALS COMBINE ALL ROCK CLASSIFICATION CATEGORIES

microcrystalline or cryptocrystalline sedimentary rock, consisting dominantly of interlocking crystals of quartz less than 30 micrometers in diameter.” Chert is normally classified as a biogenic or organic form, but there are numerous examples of inorganic chert rocks from Arizona. My mentor Cliff Montgomery sold me several beautiful, tumble-polished pieces of Arizona pastelite chert, which I made into interchangeable necklaces. A related species collected by Stan Celestian is a highly patterned pastelite variety from Burro Creek, Arizona, that he has named “Picasso Chert.” His photo collection features this specimen and includes one with differential weathering in a rough and unpolished chert specimen from this locality. The unique weathered surface is described as having a rillensteine pattern. The Dictionary of Geological Terms defines “rillensteine” as “Tiny solution grooves, of about one millimeter or less in width, formed on the surface of a soluble rock [from German, meaning ‘rilled rock’]”. In 2009 an Arizona Geological Survey Team discovered an opaline variety of chert layered within a travertine formation in the McDowell Sonoran Preserve as a desert precipitate in Scottsdale, Arizona. According to the authors, “Limestone has not been identified previously in the McDowell Mountains or in the metro Phoenix area … The limestone deposit overlies or rests on a larger area of metamorphic rhyolite rock. The meta-rhyolite, a rock rich in silica, likely is the source of the mineral constituting the chert.” Investigators prepared a thin section of a sample for photo-micrographic examination. The study team identified these geologic events; 1) original travertine limestone deposition; 2) formation of orbicular (concentricallylayered spheroidal) chert and possibly dissolution of limestone; followed by 3) coatings of calcite, silica, and possibly algae in cavities; and finally, 4) void-filling by coarse calcite in a water-saturated environment. The McDowell Sonoran investigation of a deposit of opalized chert illustrates a prime precipitation event by silica and the mineral SiO2. Opal is hydrous silica (SiO2·nH2O). Technically, opal is not a mineral because it lacks a crystalline structure, so it is typically referred to as a mineraloid. This opaline variety of chert was created in a natural opaline formation as a part of a unique limestonedepositional event.

As a known biogenic source of limestone, chert literally holds up the red rock formations of Sedona and the Grand Canyon.

The chert-based Kaibab and BIF rocks containing calcium and magnesium-carbonate and iron oxides constitute just a few chert minerals commonly found in Arizona and are now known worldwide. These mineralized rocks establish the complex of chert formations that encompass Earth’s fundamental stratigraphic units as defined by the Geologic Time Scale, and the study of physical geology. By using the term “complex” this author intends to define units of chert formations further as composed of rocks of two and often three of the standard classifications of sedimentary, metamorphic, and igneous rocks. The chert complex contains a myriad of mineral inclusions that are found globally within these stratigraphic features, both as trace elements and as complex combinations of minerals. Chert is normally considered to be a sedimentary rock. But there are now multiple variations being scientifically studied and shown worldwide that contain multiple minerals and patterns. Most chert rocks contain some quartz which accounts for its dense microcrystalline or cryptocrystalline composition. Concerning its typically high quartz content, chert can be an organic or inorganic precipitate or a replacement product in sedimentary rocks. According to the reference page https://mrdata.usgs.gov/ geology/state/sgmc-lith.php?text=chert Chert is defined as “A hard, extremely dense or compact, dull to semivitreous,

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C H A N N E L I NG A MO T H E R RO C K

Comparison of Barrcano agate specimen cabs cut by the author; and made into pendants for club friends Carol Barr and Lynne Wheeler who collected it.

PROGENITOR OF DURABLE MOUNTAIN VISTAS Chalcedony and quartz minerals play important roles as strengthening components that produce the nearly indestructible varieties of chert that have outlasted many geological eras. One good example is the Mogollon Rim, a geological feature that skirts the northern half of Arizona and forms the southern edge of the Colorado Plateau in Yavapai County, ending near the border with New Mexico. The Mogollon Rim is a complex assemblage of mineral constituents and is representative of the chert complex of Arizona. These massive Paleozoic limestone-chert formations are remnants of coral reef outcrops of the Mogollon Rim seabed deposits. Now at over 6,000 feet elevation in the Payson-Pine rimstone region, the Mogollon highlands were originally part of a vast inland sea 225-280 million years ago — the Triassic-Permian periods. Since that time, the original seafloor now sits at a much higher elevation through uplifting from plate tectonics, reaching 8,000 feet at its maximum height.

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In addition to fossil fragments, these chalcedony-rich rocks incorporate a great many chert and jasper minerals. During a November 2018 field trip to the Payson area of Arizona, we collected pink jasper nodules and the boldly banded chert known by local area rockhounds as “Zebra Stone.” These sedimentary and igneous mixtures of weather-resistant minerals form a rugged topography of gravel sediments that were transported by ancient river systems and deposited in central and northern Arizona. An older Paleozoic layer of the Rimstone strata that contains nodules of cherty coral and mollusk fossils is known as the Martin Formation. These rocks are dated at approximately 375 million years and were deposited during the Devonian Period. The variable sedimentary rocks of this formation constitute a cliff-forming limestone member of the Mogollon Rim that has created deep, sheer-walled canyons containing vertebrate fossils along with sea sponge reef casts of stromatoporoids and other invertebrate reef-forming species. Chert occurs just as commonly as layered or bedded deposits such as in the BIF specimens that exhibit ocean iron-precipitate bands from the oxidation of iron in ancient oceans. According to the web site http://www. galleries.com/rocks/bif.htm “Banded iron formations are found in the continental shield of all continents of the world. The shield areas of continents contain the oldest Precambrian rocks. At one time these rocks may have been together as one continent, but later broke apart and became the core of the modern continents as they exist today. Although each continent has had its own geologic history that had its own impact on their shield rocks, it is somewhat amazing that most BIF rocks are very similar in character. This is truly one of the most amazing rocks found on Earth.” I have discovered that variations of chert such as the jasp-chert rocks known as BIFs contain constituents of metamorphic and igneous mineral groups. The BIF deposits in the Verde Valley are compact, massive rocks. My experience collecting a range of sample specimens of these ancient fractured specimens, especially those attributed to local, scenic formations, led to an epiphany. As a known biogenic source of limestone, chert literally holds up the red rock formations of Sedona and the Grand Canyon. These strong limestone cliffs overlie soft slopes of undercutting sandstone. The vast protective plateaus actually slow the progress of erosion. This Paleozoic chert has endured since the Permian Period due to its plethora of marine organisms whose calcareous remains have been replaced by silicon dioxide, or quartz, the main rock-forming mineral of all the categories of rocks - igne-


C H A N N E L I NG A MO T H E R RO C K

Comparison of Payson Specimens of Orange-Pink-Banded Jasp-Chert Rocks with Botryoidal Chalcedony Rose Cobbles.

ous, metamorphic and sedimentary. It is also one of the major rock-forming minerals of chert, the subject of this article, and a mother rock for the ages of life’s tumultuous history. Chalcedony, a cryptocrystalline variety of quartz, has a vitreous luster and is the material that makes up much of the chert found in the Verde Valley. During my field trips throughout the area, I have collected many types of crypto-chert that exhibit the characteristics of the igneous rocks described as agate and jasper, not to mention the hard siliceous qualities of the sedimentary and metamorphic rocks known as BIFs. Despite their ancient origins, these BIF specimens with bold bands of hematite take a high polish and can be displayed for their showstopping colors and patterns, as shown in photos in my previous article. My friend and Mingus Gem and Mineral Club colleague Mike Kavanagh has exhibited his artfully polished BIF specimens at our gem and mineral club shows.

BARRCANO AGATE VARIETIES DISCOVERY I learned about a particular variety of chert that was discovered near the Payson Municipal Airport by Carol Barr, a mining engineer, which the Arizona Geological Survey has examined. This nodular rock has been informally named “Barrcano Agate” in her honor. The specimen that was shown to Arizona Geological Survey (AZGS) has been classified as an agate, although some

Pastelite Egg created by Cliff Montgomery and Becky’s interchangeable Pastelite necklace made from Cliff’s Burro Creek tumble-polished slab fragments.

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C H A N N E L I NG A MO T H E R RO C K of the other orange-banded nodules among her sample collection are clearly an opaque variety that display characteristics of chert and jasper. Carol stated that AZGS gave it an average hardness of 7.2 on the Mohs scale. The Payson area is well-known for its jasp-chert-agate deposits, especially since the Mogollon Rim is mainly an ancient chert-laden formation. Further discussion in this article covers the chalcedony cobble specimens from the same Payson collecting area that display attributes of agate, jasper, crystalline quartz and quartz druzy formations. Since the Barrcano Agate has variable luster on exposed surfaces, it’s obvious that its many versions display attributes of all categories of common chert, and some jasp-agate features on the weathered-off surfaces. Since so many varieties of agate exhibit patterns along the weathered surfaces and within the rind and exterior faces, it’s common to initially find colors where they are easier to chip off and expose. These patterns were typically the first to form when agates develop within gas pockets of igneous rocks such as basalt, wherein silica solutions generate many bandforming layers as they adhere to irregular cavity surfaces. The patterns that appear in Barrcano Nodules are less developed and may have primarily formed in sedimentary rocks where mineral-bearing quartz solutions along bedding planes filled numerous spaces and voids. Ancient life forms played an important role in creating biogenic silica and calcium carbonate in building up extensive nodular masses in sedimentary formations. Likewise, iron-oxidizing bacteria were an important source of banded iron formation. Such cementing mineral agents consolidated the Barrcano concretionary nodules as silica, iron oxide and calcite. These dense and compact float relics

Chert-and-Limestone Fossil Chert Casts, Concretions and Brachiopod Specimen Collection from the Payson-Pine areas of the Mogollon Rim.

weathered out of their sedimentary host rocks and were found near the Payson Airport. Since agate is commonly microscopically fibrous and translucent or semitransparent, I wanted to examine the mysterious nodular mineralogy. I asked Mike Kavanagh, our local gem show co-chairman, to cut a variety of slabs from the specimens Carol had collected for me. I made a few cabochons to determine the extent of mineral inclusions. I soon discovered that some of the nodules were only partially band-forming and translucent. I found inclusions of dense macro-quartz in the interior portions of many of these slabbed specimens so that concentric patterns only occurred on the exterior surfaces of the nodules. In most cases, the quartz interior zones are an opaque white-andgray color, while in others, the quartz formations are large crystalline centers. A small collection of the nodules and slabs do exhibit some jasp-agate and agatized constituents in the chert rocks.

FIELD TRIP TO COLLECT ICONIC AZ VARIETY, “ZEBRA STONE”

Barrcano Nodular Specimens of Agatized Chert first collected by Carol Barr in the area around Payson Municipal Airport, Payson, AZ.

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Having recently collected varieties of black, brown and tan-banded chert in the Pine-Payson Mogollon Rimstone wilderness in 2018, I learned from the Mindat.org database that this version of chert (which was always referred to as “Zebra Stone” by our club members) is officially classified as an Arizona chert. The specimen shown on Mindat has the look of a high-quality jasper or jasperoid mineral. Considering the lustrous banded appearance of the Mindat type-specimen, one has to look harder at definitions of chert and jasper, as the Zebra Stone from this area can be both sedimentary and igneous in texture and appearance. The third edition of my Dictionary of Geological Terms,


C H A N N E L I NG A MO T H E R RO C K of the American Geological Institute, by Editors Robert L. Bates and Julia A. Jackson, define “Jasper” as “1. a variety of chert associated with iron ores and containing iron-oxide impurities that give it various colors, especially red; and 2. Any red chert or chalcedony irrespective of associated iron ore. Synonym: jasperoid.” The authors further define “Jasperoid”, another noun, on the same page, as “1. A dense, chertlike siliceous rock, in which chalcedony or cryptocrystalline quartz has replaced the carbonate minerals of limestone or dolomite; a silicified limestone.”

THE CONVERSION OF SILICIFICATION TO CHERTIFICATION This definition of “Jasper” and “Jasperoid” clearly indicates the complexity of gradations that can occur in any one deposit of such material. After the Rim collecting trip, I brought my Zebra Stone specimens home to Sedona and laid them out in the sun to compare their characteristics. Some of the rocks have sedimentary attributes and are encased in a pure limestone matrix with little or no silica. Others are only slightly silicified in the banded areas and exhibit characteristics of ordinary sedimentary deposits. Still others, such as the Payson examples of Barrcano Agate and the pink and orange-banded jasp-chert we collected on our 2018 field trip contain higher levels of silicification. According to the same Dictionary of Geological Terms, “chertification” is defined as “Essentially silicification, especially by fine-grained quartz or chalcedony”. The term “chertification” contributes to my understanding of what it means to be able to identify chert-like rocks and their commonly associated minerals. During our 2018 field trip, we also found specimens of orange and pink-banded Jasp-Chert along with bouldersized masses of white botryoidal agate that resembled chalcedony roses. Some of the varieties of pink and tan jasperized nodules and fossiliferous cherty limestone rocks are part of the chalcedony-chert-sedimentary complex which is the subject of this article and representative of the North-Central Arizona mineral-rich complex of chert-infused deposits. This is definite proof of the cryptocrystalline characteristics of a type of chert that tends to morph into a harder more well-consolidated example of jasper or jasperoid, which I consider to be in a category above common chert and yet part of the constituent mineralization of the chert complex. The chalcedony-rich mineralization of this area is the source of this complexity in the quartz-suffused chert of the Mogollon Rimstone. Many BIF deposits, especially those found in Minnesota and Michigan, are mined for their concentrations of iron ore, some of these having been named “Jaspelite” for their

Author’s Banded-Chert “Zebra Stone” Pendant that she made from the iconic area Banded Chert.

iron-rich content and bands of hematite and quartz that are common in banded iron rocks. Due to the extreme antiquity of these Precambrian deposits, which were originally sedimentary in character, almost all BIF formations have undergone some degree of tectonic transformation, deformation, and/or mineral alteration, whether due to contact metamorphism, which is a reconstitution of rocks that occurs at or near their contact with a body of igneous rocks, or contact metasomatism. Mindat.org defines the term “Contact Metasomatism” as follows: “A mass change in the composition of rocks in contact with an invading magma, from which fluid constituents are carried out to combine with some of the country-rock constituents to form a new suite of minerals.” It is undoubtedly the case that BIF deposits as old as those in the Verde Valley, which were metamorphosed at 1.75 billion years ago, were altered at great depth below the surface zones of consolidation, cementation and erosion, which differ from the conditions under which the same rocks originated.

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C H A N N E L I NG A MO T H E R RO C K

Comparison of AZ Banded Chert Specimens: Rock shown on left is a Mindat.org specimen; right one is a hand-collected specimen from Payson, AZ, from the same Mogollon Rim area material called “Zebra Stone” by collectors in past field trips.

FOSSIL FORMS CREATE PALEOZOIC PANORAMAS What is especially interesting to me as a fossil collector in the Verde Valley is that chert most conspicuously occurs as nodular or concretionary formations in the regional sedimentary rocks. This unique circumstance has made fossil collecting on the Mogollon Rim and elsewhere in the Verde Valley an adventure for me. My yard rocks evoke an ancient seafloor vista where reef-building relics pop up everywhere. I have a collection of well-preserved brachiopods. My sponge fossils are distinctive for their silica-infused spicule patterns. Some featureless coral fragments with reef-like shapes are the product of an extensive chertification process. Chert nodules occur as extremely dense structureless masses within limestone and dolomite. I was curious as to why the features of some of the nodular and concretionary fossils had been erased. In my research, I learned that the silica-secreting organisms were frequently dissolved by fluids flowing through the rocks during diagenesis, prior to final lithification of mineral constituents. As a result, fossil formation is absent due to the complete dissolution of their organic debris over millions of years of depositional activity. And yet, despite the lack of fossil residue, the colonial animal forms were cast in stone like the victims of Pompeii. Several of my knobby fossils from the Rimstone rocks are exactly the same type of hardened masses. These irregular mounds became recrystallized calcareous fossil concentrations of siliceous reef structures in Paleozoic seas. The once-thriving ecosystems were compacted by endless

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cycles of chert-enriched sediments fed by mineral laden silica solutions along permeable bedding planes. The limestone-jasp-chert outcrops of the Mogollon Rim are among the most mysterious mixtures of sedimentary and igneous minerals. Having accumulated a yard full of concretionary chert nodules from the Verde Valley where I live, it seemed natural to contemplate these extraordinary wonders of a lost world. The most intriguing collectibles recall the sedentary filterfeeders that built limey frameworks layered with chert minerals. Now my mother rock treasures have a new life as conspicuous curiosities in my red rock washes, retaining wall gardens, and landscaped planters. Becky Solon is a retired U.S. Army Mechanical Engineer, MBA graduate and a mineral collector with training and interest in jewelry design. REFERENCES: 1. AZGS Contributed Report CR-09-B, 416 W. Congress St. #100, Tucson, AZ, 2009, “Limestone Discovery in the McDowell Sonoran Preserve, by Brian Gootee, Dan Gruber, Larry Levy, Joni Millavec and Bill Ruppert 2. Geological Survey Professional Paper 233-D, USG Printing Office, Washington: 1952, “Devonian and Mississippian Rocks of Central Arizona, by John W. Huddle and Ernest Dobrovolny 3. Dictionary of Geological Terms, Third Edition, American Geological Institute, 1984, by Robert L. Bates, Julia A. Jackson, Editors 4. Arizona Banded Chert Specimen reference from the Mindat.org database: https://www.mindat.org/locentries.php?m=994&p=3293 5. http://www.galleries.com/rocks/bif.htm 6. https://www.flickr.com/photos/usageology/47116425862/in/ photostream/.


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THE GARNET FAMILY Spanning the Spectrum of Mineralogy STORY BY BOB JONES

(Left) Editor Bob joined dealer Benny Fenn in the mountains of Coahuila to dig fine red grossular garnets in limestone. (Right) The chemistry of these fine yellow grossular garnets is based in calcium as the main metal component. BOB JONES

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G

arnets are among the most common crystallized minerals you can collect. It is one of the very few minerals that spans the entire spectrum of mineralogy. It has been used as a gem for thousands of years. It has always been popular as a collector mineral. It is useful in the industrial world, and scientists study some garnets to determine the pressures and temperatures that create metamorphic rocks located many kilometers deep in the earth. Several varieties of garnets are delightfully beauti-ful and exotic, while others are common and easy to identify when you are field collecting. It may seem odd to associate

garnets with the business world, but one little-known fact concerns the world famous Wrangell, Alaska, garnets. They played an important role in cracking what the business world calls the “glass ceiling.” Near the mouth of the Stikine River, close by Wrangell, Alaska, is Garnet Ledge, one of the betterknown almandine garnet deposits. Specimens from here have been collected for over a century, starting with gold prospectors, once owned by the Boy Scouts, and Juneau’s Presbyterian Church, and now it is a registered Wilderness area held in trust for the children of Alaska. Today, you can see the simple 12-sided almandine crystals in mica schist from the Ledge world-wide in museums, in private collections, and to a lesser degree in jewelry. These crystals are choice examples of an iron aluminum silicate garnet. They are not particularly well known for their gem quality, but Alaskan almandine


In recent years China has been producing fine specimens of red spessartine garnets on matrix. ARKENSTONE GALLERY OF FINE MINERALS

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THE GARNET FAMILY

Amesite var. chromian amesite, garnet var. uvarovite: Saranovskii Mine (Saranovskoe), Saranovskaya Village (Sarany), Gornoazavodskii area, Permskaya Oblast’, Middle Urals, Urals Region, Russia. GÉRY PARENT, CC BYSA 4.0, VIA WIKIMEDIA COMMONS

garnets should be considered special in the business world. It happened that the deposit was once owned and operated by the Alaska Garnet Mining and Manufac-turing Company in the early 20th century. This company was very special when it operated, not because of the garnets but because it was the first-ever business corporation in America fully owned and operated by women! Check it out on the internet under Wrangell, Alaska, garnets. What a great story it is! As for almandine garnets, the crystals are easy to recognize because the mineral usually forms in 12-sided crystals that are very hard, 6.5-7.5 on the Mohs scale. They survive after the host rock has been weathered away. That hardness makes this very common mineral suitable for industrial grinding use, so large deposits of garnets, usually metamorphic as in Alaska and Gore Mountain, New York, are mined. Some of these old mines, once abandoned, become rockhound sites of note, such as in Roxbury, Connecticut. Garnets occur in a wide variety of localities and types but are most common in metamorphic rock types. Mineralogists, including Michael O’Donoghue in his sixth edition text Gems, lists no fewer than 16 different members of the garnet family, all silicates. Of these, six varieties are prevalent and described at length in the literature. They are almandine, pyrope, spessartine, uvarovite, grossular, and andradite. They are listed as two sub-groups, pyrospite and ugrandite, based on their chemistry and using portions of their mineral names. The pyralspites are pyrope, almandine, and spessartine, and all based chemically on having aluminum as the main metal. Either iron joins the aluminum to

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form almandine, magnesium to form pyrope, or manganese to form spessartine. The atoms of those three elements can interchange due to similar size and electron structure to form a series that grade one into the other. The ugrandite group has three garnets: uvarovite, grossular, and andradite, all basing their chemistry on calcium as the metal. Either iron-forming andradite joins the calcium or chromium to form uvarovite, or aluminum joins the calcium to form grossular garnets. Of the three major rock types in the earth’s crust, garnet is most often formed during metamorphism, so it is found in schist, especially mica schist, gneiss, and other metamorphic rock. It is found much less often in igneous rocks like granite and even in some pegmatite deposits under the right conditions. Because of garnet’s hardness, it survives weathering and so is also found in sedimentary environments. A fascinating thing about garnets formed in metamorphic rocks is they can hold internal secrets scientists use to establish the conditions under which metamorphic rock forms. Hard to believe, but garnets can tell scientists the approximate pressures and temperatures that particular rock were subjected to during metamorphic action. As the garnet is forming under high pressures and tempera-ture, its crystallization, lattice structure, and internal zoning of the crystal are affected, and this, in turn, tells scientists about the forces involved in metamorphic action. As if that were not enough, garnets may also tell scientists how long ago the rock formed through any trace of led-uranium it may contain. These are all examples of the wonder of the science of mineralogy! For decades, the most common garnet available was almandine; this is because it was heavily mined for its abrasive qualities. You can buy garnet paper in any hardware store, and it is most often crushed almandine. This writer-collector and countless New England mineral collectors cut their collecting eye teeth on the old abrasive almandine garnet locality in Roxbury, Connecticut, a metamorphic schist deposit. The garnets in this location


THE GARNET FAMILY

(Top) Cluster of well-formed orange spessartine garnet crystal with shaded edges MASHA MILSHINA, CC BY 4.0, VIA WIKIMEDIA COMMONS

(Bottom Left) The andradite garnet deposit on the Apache Indian Reservation in Arizona produces superb garnet crystal groups. BOB JONES (Bottom Right) Garnet variety grossular: Sierra de Cruces, Mun. de Sierra Mojada, Coahuila, Mexico. GÉRY PARENT, CC BY-SA 4.0, VIA WIKIMEDIA COMMONS

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THE GARNET FAMILY

(Top Left) These faceted gem garnets display the nice variety of colors seen in this hard, common mineral. COMMERCIAL MINERALS

(Top Right) The ant hills of northern Arizona sometimes have small red pyrope garnets mixed in the sands around the ant hills which the ants “mined”. BOB JONES

(Bottom) These red spessartine crystals on blue aquamarine from Gilgit, Pakistan show that garnets do occur in pegmatite deposits. MOFFIT COLLECTION

were abundant as perfect dodecahedrons of a deep non-gem red. Some vesuvianite crystals also occurred here. Once the mine was closed, the highway department used the dumps from this location to backfill along roads, and people could collect the loose crystals almost anywhere in town. On my first trip in 1948, I filled the pockets of my jeans with perfect crystals before ever even getting to the deposit. The Roxbury garnets were chosen as the Connecticut State gem mineral. Connecticut is just one of several states that have chosen garnet as the state gem, including New York and Idaho. The State Gem program was established by the American Federation of Mineralogical Societies, which indicates what rockhounds can do when organized! By comparison, the almandine garnet deposits in upper New York State at Gore Mountain eclipse the size and quality of the Connecticut deposit. The New York garnets are often gemmy and can be used in jewelry. As for size, the Roxbury crystals tended to be an inch or so in size, while the Gore Mountain crystals often measure several inches across and in what might be described as crystalline masses. In recent decades, several discoveries of garnets have

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stirred the mineral and gem world. The most exciting find was made by geologist Campbell Bridges, whom I had the pleasure of entertaining when he and his wife were guests of the Tucson Gem and Mineral Society. Campbell discovered a deposit of green grossular garnets in 1967 in the Meriani Hills, Tanzania, already known for tanzanite. The grossulars were gemmy and rich green that rivals emeralds. Campbell ‘s further searching found similar geologic formations that extended into Kenya, and there he found another deposit rich in grossular garnets as gemmy and bright as the original find. Working with Tiffany & Co., Campbell mined the garnets and, between them, the companies named the grossular gems tsavorite after the Tsavo National Park near the Kenya deposit. Grossular garnets are calcium aluminum silicate, and the calcium atoms can be replaced by other elements, which means grossular can be a range of colors: green, pink, gray, brown, even black. But tsavorite is unique in that the rich green color is caused by either vanadium or chromium in its chemistry. Mining this valuable gemstone took place in remote areas, and as Campbell told me once, he kept a huge snake in his tree house campsite to discourage intruders. Unfortunately, Campbell was attacked and killed, and the world lost an incredible miner and man far too soon. (Editor’s Note: To learn more about Mr. Bridges’ discoveries, his life, and the work that


THE GARNET FAMILY continues in his name and deposits in Kenya, check out Rock & Gem’s Glorious Gemstones Issue #2, available for free, at www.rockngem.com.) Another recent exciting garnet find is that of spessartine garnets, named for Spessart, Bavaria, where they were first found in quantity. Chemically, spessartine garnet is magnesium aluminum silicate and can be found in several different colors: yellow, red, violet-red, and under the right light, some crystals will show a change of color. Most form in metamorphic rock and skarms, but a recent amazing discovery was made of red spessartine crystals on aquamarine crystals in a gem pegmatite in Pakistan. Pakistan has been known for decades for a superb variety of pegmatite minerals, with aquamarine crystals leading the way. The fine of aquamarine crystals in the Shigar District, Gilgit-Baltistan, Pakistan, has produced the world’s finest specimen aquamarine specimen now known as “The King of Kashmire.” The story of the discovery of the “King,” an amazing aquamarine specimen, is well written by Danny Trinchillo. Danny is one of the leading gem and mineral dealers in the world, well known for operating the amazing Pederniera tourmaline pegmatite mine in Brazil, which produced gem crystals over a foot long. The matrix of this beauty, which originally weighed several hundred kilos when lowered from the ceiling of its pocket, is typical quartz, feldspar, and mica. You can read about this amazing discovery in the November-December 2020 issue of Mineralogical Record. The garnet family of crystals is one of the mainstays of mineralogy and our hobby. They are enough so every collector, even the most inexperienced, can field collect them and learn from them. Yet, the most advanced collector can also own and enjoy a suite of fine, rare garnet crystals. Garnets are truly worthy of being in every collection.

This display in the Weston, CT Museum displays Roxbury, Conn. almandine specimens the official gem of Connecticut. BOB JONES

Almandine on matrix. Origin: Zillertal, Tyrol, Austria. Picture taken in Belgium. JAMAIN, CC BY-SA 3.0, VIA WIKIMEDIA COMMONS

Garnet, grossular atop asbestos, from the Jeffrey Mine, Canada. LECH DARSKI, CC BY-SA 4.0, VIA WIKIMEDIA COMMONS

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THE ROAD REPORT

BY HELEN SERRAS-HERMAN

Cerro de Trincheras Trail, Museum & Petroglyphs South of the Border in Sonora, Mexico

T

he Cerro de Trincheras is an extraordinary prehistoric archaeological site located just outside the village of Trincheras in the northwest Mexican state of Sonora. The site opened to the public in December 2011 and includes an interpretive trail and an extensive visitor’s center (museum). The site is under the auspices of the National Institute of Anthropology and History (INAH). My husband and I visited the site by taking a day-trip tour south of the border into Mexico (when the border was open before the COVID-19 pandemic), departing from Nogales, Arizona. The tour was organized by Linda Rushton from Ambos Tours of Arizona, based in Nogales, Arizona. We were part of a small group of nine people total. We left Nogales, Arizona, crossed the border into Nogales, Sonora, at 8 a.m., and, after a couple of stops, we reached Trincheras just before noon. The Cerro de Trincheras site is the remains of 900 hillside terraces with retaining stone walls ranging from 4 inches to

The Cerro de Trincheras site is the remains of 900 hillside terraces with retaining stone walls dating from an early culture between AD 1300 and 1450.

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Arrowhead points from the Early Agricultural Period (1,500-850 BC) from La Playa.

10 feet tall, dating from an early culture between AD 1300 and 1450. “Cerro” in Spanish means hill or mountain, and “trincheras” was the Spanish term for entrenchments or fortifications, as that is what the hillside terraces reminded the early Spanish explorers. The name of this settlement is attributed to Captain Mateo Manje, who accompanied Father Francisco Kino to the Magdalena Valley. The soldier said that they looked like military trenches. The stone terraces at Cerro de Trincheras were used for agricultural and housing purposes, where prehistoric farmers of the Sonoran Desert lived. The first settlers arrived in the area about 13,000 years ago, and the hunters and gatherers adapted to the Sonoran Desert environment about 10,000 to 8,000 years ago (www.lugares.inah.gob.mex ). The site excavation took place between 1995 and 1996 and was a bi-national effort. Research showed that over 1,000 people lived there, and creating the terraces was a major investment of labor (Cerro de Trincheras, Randall McGuire & Elisa Villalpando, Archeology in Tucson, Winter 1998). When we visited, a new short-term pottery exhibit was on view. The beautiful display included four polychrome pots discovered by archaeologists at the site, and new pottery created by local youth, using the ancient clay type and methods. Among the other museum exhibits, I found most interesting the arrowhead points, finds from the local Clovis culture around 5,000 years ago. The name ‘Clovis’ is derived from Clovis, New Mexico, where these type of spear points were first found in 1929. On exhibit are biface, fluted biface and projectile points from La Cochera and La Playa Municipali-


Road Report

La Cancha (The Court) is a large plaza area possibly used by the ancient inhabitants for ceremonies.

(Left) Archeologists have recovered examples of all manufacturing process stages of shell loops (circles) for bracelets and beads. (Right) Shells and mother-of-pearl from the Gulf of California and tools utilized in jewelry were recovered at the La Playa site.

The Cerro de Trincheras extensive visitor’s center (museum) opened to the public in December 2011.

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Road Report

(Left) The petroglyphs area includes images carved on the rocks with animal, human figures, and geometric designs. (Right) The Cerro de Trincheras is an extraordinary prehistoric archaeological site located in Sonora, Mexico.

ties of Trincheras and the geo-archeological investigations at Fin Del Mundo, all dating from 5500 to 4100 years ago. Points from La Playa date to the early Agriculture Period (1500 to 850 BC), which continued into the early Ceramic Period (AD 50-500). The rich blade industry artifacts include cores, flakes, and blades. Local materials used include vitrified basalt, quartzite, rhyolite, obsidian, and chert (for in-depth details, read Clovis - At the Edge of New Understanding, A. Smallwood, T. Jennings, 2015). I was also very attracted to the local jewelry-making finds of shell bracelets and beads from the nearby La Playa site, which had a thriving shell jewelry manufacturing tradition. Marine shells were collected in the Gulf of California and utilized by the communities of Early Farmers to adorn their bodies. Among them are cone shells and Glycemeris shells (large saltwater bittersweet clams) - a popular trade item among the Hohokam people of the Sonoran Desert; some shell fragments are even engraved. Archeologists have recovered examples of all manufacturing process stages of shell loops (circles) for bracelets and beads. The known method of shell-bracelet manufacturing from the La Playa site, involved “marking off the shell exterior with deep, regular, short scratches, and the artisan sawed them with a sharp flaking tool. When the grooves were deep enough, the artisan tapped the center with his hammerstone, and the core fell out. Then, the ragged edges were ground and smoothed” (Shell Bracelet Manufacturing, Christine Virden-Lange, Archeology Southwest, 2017). Walking through the museum, we followed the outside trail, where interpretive signs guide visitors through the terraced hills. The hill’s occupation only lasted about 150 years, and much of the evidence has disappeared, but the terraces’ stone walls remain as silent witnesses. When we

48 ROCK&GEM | WWW.ROCKNGEM.COM

visited in the summer, all terraces were covered by green vegetation due to monsoon rains. A few fellow tour participants braved the heat and hiked all the way to the top of the hill to see the Plaza del Caracol (the snail shell), which has semi-circular walls and a spiral-shaped access corridor. Andy and I walked to La Cancha (The Court), a large plaza area for public events. The Court is the name modern archeologists gave to this public space, which never had a roof, possibly used by the ancient inhabitants for ceremonies. The interpretive signs read, “As in modern Indian ceremonies in northern Mexico, dancers probably used the flat space, and musicians and singers accompanied them from the circular structure.” We also enjoyed the petroglyphs area, where various images are carved on the rocks, occurring isolated or in groups. Designs include animals, human figures, and geometric forms. The Cerro de Trincheras is a wonderful site, definitely worth visiting. Visitors can learn about this agricultural community and the Sonoran Desert’s pre-Hispanic occupation that was much more complex than previously imagined. Most exhibits are both in Spanish and English. All museum personnel were wonderful, happily sharing their knowledge about the site. It is open Wednesday through Sunday, 9 a.m. until 4 p.m., and there is no admission fee. Find them at www.facebook.com/Zona-Arqueológica-Cerro-de-Trincheras, with a link to their website. Helen Serras-Herman, a 2003 National Lapidary Hall of Fame inductee, is an acclaimed gem sculptor and gemologist with over 38 years of experience in unique gem sculpture and jewelry art. Visit her website at www.gemartcenter.com and her business Facebook page at Gem Art Center/Helen Serras-Herman.


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GEMFAIR GEMFAIRE.COMGEMFAIR WWW.ROCKNGEM.COM | JULY 2021 49


CLUB CORNER SPECIAL REPORT

BY BRUCE MCKAY

Digging at the McDonald Ranch

I

n June of 2020, the Central Oregon Rock Collectors club went on a field trip to the McDonald Ranch near Ashwood, Oregon. The McDonald Ranch offers petrified wood, angelwing agate, and thundereggs. We met in downtown Madras, Oregon, in the morning and caravanned North on Highway 97. No carpooling was allowed due to COVID-19 concerns. We drove past the Richardson Rock Ranch and turned South on NE Pony Butte Road towards Ashwood. In 9 miles, we passed the polka dotted trailer that marks the entrance of the Polka Dot Agate mine, and within a half mile past that was the sign for the McDonald ranch at the first right turn after Polka Dot. The gravel road to the McDonald Ranch Agate Beds is well maintained

and, at 5 miles in, ribbons mark the ranch entrance. The McDonald Ranch is a 3,000acre ranch that has been in the McDonald family for generations. The family history dates back to the 1800s when Ashwood was a gold-mining town and the McDonald’s great grandfather was one of the first livestock operators before the Homestead Act. Today, the ranch is run by Alex and Cheryl McDonald and their son, Tom. In the 1960s, the family began to open their ranch for rockhounds and have continued to do so ever since. The group first started at the petrified wood location. The ground has been bulldozed, exposing large quantities of petrified wood. This is primarily petrified Sequoia, which is well silicified and takes a great polish. There is plenty to pick up from small

to massive broken chunks and intact limbs and trunks. Logs have been dug there up to 30 feet long, and there is a 16½-ton piece at the University of New Mexico at Las Cruces. A geology professor from the Smithsonian was present when that log was shipped. Next, the group went to the angelwing agate area, about a 1/3 mile farther down the dirt road. This area has also been bulldozed and has loose piles of dirt to search through to find agate. Beyond the loose dirt was some agate exposed in basalt that required serious digging. I stayed with the loose piles and was rewarded with a very nice 2-pound piece of angelwing. Club members left with some very nice pieces from this dig site. Another 100 yards beyond the angelwing is a long trench where thundereggs can be dug from the trench

(Left) Lenny and Wally find a big piece of petrified wood. (Right) Thundereggs from the McDonald Ranch. ALL PHOTOS CORC

50 ROCK&GEM | WWW.ROCKNGEM.COM


Club Corner Special Report

Cheryl McDonald weighs some wood for a club member

McDonld Ranch petrified Sequoia.

wall. This was the hardest digging of the day. I spotted a thunderegg on the wall and began to carefully chip away around it. I chipped and chipped, but it is still there for the next more patient rockhound. The thunderegs are $1 per pound, the petrified wood is $2 per pound, and the angelwing agate is sold at $3 per pound. Scales set up at the petrified wood and angelwing sites let us know how much over budget we had gone. The McDonald Ranch is open by appointment only. This is a working ranch, and the McDonald family needs to know when guests are coming. Call Alex McDonald at (541) 489-3290, leave a message, and Alex will return your call.

WWW.ROCKNGEM.COM | JULY 2021 51


Earth Science In The News

WIKIMEDIA COMMONS)

BY JIM BRACE-THOMPSON

New Stories from “the Third Pole” e’ve all heard of the North Pole and the South Pole. But “the Third Pole”? Huh? That is how the Himalayas have been described because these mighty mountains contain the largest ice mass outside of our polar regions. In an article in the journal Science, Tanuj Shukla and Indra S. Sen call for greater use of real-time satellite monitoring of glacial lake catchments to predict and prepare for catastrophic flood events due to all that ice. Such monitoring is especially important in a time of global warming and uncertainty. For instance, it’s noted that the number of glacial lakes has increased substantially in recent decades, as have “extreme events.” Such events often have had catastrophic effects on people living within and downstream from the Himalayas, sometimes resulting in thousands of deaths. Along with increased potential for flood events, the Himalayan region also is vulnerable to landslides that could be lubricated by rapid snowmelt in an area already at high seismological risk. So says N. Purnachandra Rao (National Geophysical Research Institute, India) and colleagues. For instance, earlier this year a glaciated ridge in the western Himalayas gave way in

W

52 ROCK&GEM | WWW.ROCKNGEM.COM

The Great Himalayas. (Shreyasvijay11, CC BY-SA 4.0,

a landslide that killed more than 100 souls while also destroying two hydroelectric projects. In addition to the satellite monitoring called for by Shukla and Sen, Rao and colleagues call for installation of a dense network of ground-based seismometers to assist in early warning of earthquake events and accompanying rockslides. Both studies emphasize the importance of “real-time” monitoring if we are to mitigate or at least minimize damage and casualties in an area already long prone to geological hazard from natural Earth processes.

NO MORE PLANET X? The idea of “Planet X” (or “Planet Nine”) has been around for well over 150 years. The theory involves an unknown, unseen giant planet in the outer reaches of our solar system far beyond Neptune and dwarf planet Pluto. Proponents claim that distant lumps of rock and ice are specifically clustered together way, way out there, and they must be clustered due to the gravitational pull of hypothetical Planet X or Planet Nine that circles our sun in an eccentric and inclined orbit. Not so fast, say others in a recent report in Planetary Science Journal. The clustered debris may simply be the result of selective bias in where astronomers happen to have


Earth Science In The News

focused their telescopes. These scientists say that there is likely far more debris out there, and it isn’t necessarily clustered together in any particular way. Scientists hope that a new telescope—the Vera C. Rubin Observatory due to debut in Chile in 2023—will help settle the debate.

JUST HOW MANY TYRANT LIZARD KINGS POPULATED EARTH? As America begins evaluating its latest census data, a census of a different sort has been tallied recently; namely, a census of how many creatures would have had us as appetizers had we co-existed! I’m talking about Tyrannosaurus rex, or the “tyrant lizard king” of the Cretaceous Period. Researcher Charles R. Marshall (University of California, Berkeley) always wondered just how many T. rex individuals there were in all and how dense their populations may have been at any one time. Fortunately for him, T. rex is one of the most extensively studied of all dinosaurs. Thus, he and his team of fellow researchers had a good amount of data from which to work. Still, their methods involved a lot of extrapolation based on body mass and population distribution and densities of existing creatures, as well as good old-fashioned guesswork. (I’ll spare you the detailed mathematical formulas and the margin-of-error.) In a cover story for the April 16, 2021 issue of the journal

Science, Marshall and his colleagues suggest at least 2.5 billion T. rex trod Earth during their reign 68 to 66 million years ago. At any one time, there may have been 20,000 individuals thundering across North America.

WHEN FOSSILS AREN’T Just when did life first bloom on Earth? That’s a question paleontologists have grappled with ever since paleontology was established as a formal science. The problem? Earliest life would have been microbial, and microbes seldom fossilize. Still, under the right conditions, even single-celled organisms can leave a mark in rocks millions and billions of years old. But then, so can so-called “biomorphs.” Biomorphs are crystalline structures produced by inorganic or abiotic chemical processes that can look for all the world like spherical microfossils, especially in ancient rocks that have been heated, squeezed, and otherwise illtreated by earth processes over the course of two or three billion years. In a recent online issue of the journal Geology, researchers including Julie Cosmidis (University of Oxford) and Chrstine Nims (University of Michigan) warn that many microscopic structures in rocks dating back two to three billion years may not be fossils, as some studies have suggested. Rather, they are likely “pseudofossils,” or mineralogical forms that mimic the shape of biological spheres, tubes, and filaments.

WWW.ROCKNGEM.COM | JULY 2021 53


STUDYING THE PAST OF

Petrified Wood Trust Plant Anatomy To Be Your Guide When Working In the Present STORY AND PHOTOS BY DOUG FOSTER

P

etrified wood is one of the least expensive semi shaped patterns, as can be seen on plywood and dimensional precious gemstones and yet can be one of the most lumber. These patterns will differ, of course, based on whether the board cut is made closer to the outside of a log or closer to fascinating if properly prepared and labelled. Many its center.Board cuts, however, will create such patterns only years ago, I got interested when a big flood dropped tons of rock on our pasture, including a lot of petrified wood, if you’re cutting trees that grew in a temperate climate, which and a local rock shop cut a big chunk for me that revealed have growth rings marking the seasonality of wood growth unexpected patterns inside. Over time, this interest turned from spring to the annual dormant winter season. into an obsession. Lacking any formal background Tropical trees, in contrast, grow year around and in geology and botany, I studied diligently, so lack annual growth rings; when board-cut, learned to identify wood, kept my three they won’t show such attractive patterns. slab saws running most daylight hours, In the western U. S., most petrified and identified thousands of speciwood older than the mid Eocene mens of petrified wood. For the last (about 48 million years ago) grew 20 years, I’ve been the curator of in the tropics and lacks growth petrified wood at the Crater Rock rings. If you collect petrified wood Museum in Central Point, Oregon, specimens in the field, you can and I’ve coauthored and published easily learn how long ago those the first scientific study of petrified trees were alive by contacting the wood in Oregon’s Rogue Valley. federal or state land management To know how best to cut petriagency closest to your collecting fied wood, you’ll have to learn some area, or you can check geologic maps. plant anatomy, and to describe and label The very old petrified trees from Arizona and Utah, dating to the Jurassic and petrified wood, you’ll need to learn more This higher magnification view shows plant anatomy and buy a 20X lens: your late Triassic, lack annual growth rings that the bark’s woody structures run because they grew in the tropics; they old 10X loop isn’t powerful enough. One perpendicular to the branch’s rays. attraction of petrified wood, seldom taken may, though, have a few sporadic rings advantage of by lapidaries, is telling its story: petrified wood marking droughts. Much such petrified wood is so colorful was once alive, and most people are interested in fossils. This it’s called “rainbow wood” and will show bright, attractive colors however it is cut. Other highly colorful varieties can vary from describing woody features to telling how long of petrified wood, like “Roxy Ann wood” from southwest ago the tree was alive to identifying what kind of tree it was. Oregon, can also make attractive cabs regardless of the angle CUTTING, GRINDING AND GLUING cut, as shown in the nearby photo. When cutting petrified wood, take a hint from how sawmills cut logs and vary the angle of cut to fit the variety of tree TEMPERATE CLIMATE TREE PATTERNS being cut. Most logs are “board-cut,” a cut made parallel to the Temperate climate trees can also reveal attractive patterns if length of a log that doesn’t go through the pith in the center “cross-cut,” a cut made perpendicular to the length of the log. (a/k/a “tangential cut,” per wood scientists). Board-cuts show This is the cut timber fallers make at the base of a tree trunk to annual growth rings as repetitive, wavy, oval or “V” or “U” drop the tree (a/k/a “transverse cut”). When a tree with growth

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GETTY IMAGES

This cross-cut, near-round, specimen of a petrified conifer (Spruce) shows its wavy, concentric growth rings as white on black; before bleaching, its face was all black.

WWW.ROCKNGEM.COM | JULY 2021 55


S TUDY ING THE PA S T OF PE TRIFIE D WOOD rings is cross-cut, its rings show as concentric circles, like a bull’s eye target, and its rays – which carry nutrients from a tree’s outer, living sapwood to its center – show as narrow lines going across, and at right angles to, these rings. In round limbs, rays look like the spokes of a wheel as shown in the nearby drawing but appear to be nearly parallel lines in chunks of petrified wood from big limbs or logs. While board-cut, temperate climate trees sometimes show growth rings as wide, wavy patterns too large to

Deciduous oak is considered a “ring porous” hardwood because it has big pores in the spring, when its new leaves need water to grow, but only small pores in its summertime latewood. The wide vertical lines are its rays, which extend from its pith to its outer, sapwood.

capture in a small cab. Cross-cuts of such trees will usually capture smaller patterns that both fit within a cab and are often appealing to the naked eye. Before making my first cab, I’d spent 10 years cutting petrified wood specimens, and every one of those cuts was a cross-cut because I was obsessed with identifying wood varieties. To identify wood with a 20X lens, you must study the cross-sectional face of a limb’s vascular system (“plumbing system”), which moves water up from roots to leaves. Trees with bold growth rings can be showy both when cross-cut and when board-cut. Wood anatomists call these trees “ring porous” because they develop large pores in the spring to carry water from roots to growing leaves, but only small pores in the summer; this contrast prominently marks annual growth rings. Ring porous trees include oak, locusts, ash, sassafras, and elm. In contrast, “diffuse porous” hardwoods – like willow, poplar, cherry, and maple - lack bold growth rings because there is no noticeable difference in pore size throughout the year. Conifers, which evolved earlier with a less efficient plumbing system, move water from roots to needles through a mass of tiny, straw-like structures called “tracheids.” When

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viewed with a 20X lens in cross-section, masses of tracheids look like a close-up view through a window screen, and even a sudden change in tracheid size from larger in spring to smaller in summer may not be eye-catching when seen with the naked eye. When a temperate climate hardwood tree not only has bold growth rings but also has prominent rays – like deciduous oak trees -- it is usually best to do a cross-cut to reveal the showy pattern of rays intersecting concentric growth rings. In the Pacific Northwest, petrified deciduous oaks do not appear in geologic formations older than the Miocene; they can be found at such famous Miocene collecting sites as McDermitt, the Stinkingwater Mountains, the Deschutes Canyon in Oregon, and at Vantage in Washington State. (Petrified “live oak,” the evergreen oak famous in the South for hanging moss, can be found in formations older than the Miocene; but while live oak has bold rays, it is not ringporous and so is not as desirable for lapidary use.) Sawmills will also “quarter-saw” certain varieties of trees – sycamores, beeches, and maples – a cut parallel to a ray and through the pith (a/k/a “radial-cut”), which shows rays as scattered, discontinuous patterns called “ray fleck”(described by some as a “corn flakes” pattern). Petrified sycamore is most attractive when cut this way, as the nearby photo shows. In Oregon, petrified sycamore wood is common at Oligocene-aged collecting areas near Sweethome and in the Rogue Valley. While cross-cut sycamore shows distinctive rays, they are not wide, prominent rays like oak, and so sycamore cut this way is generally less desirable as cab material.

UNDERSTANDING TYPES OF PETRIFIED WOOD If you have any long, round limbs of petrified wood, it is always best to cross-cut them: for small limbs, cut off one end; for big limbs, slab out the limb in 5/8” or wider sections. Petrified wood collectors will pay top dollar to buy specimens, but they are usually only interested in rounds or near rounds. This is also true for limb casts. Identified petrified wood, though, commands the highest price. Petrified palm wood presents different cutting issues because palm trees lack both rays and growth rings. Palms move water from roots to fronds through many, scattered “vascular bundles,” which are relatively long and ovalshaped. Palm wood seen with the naked eye looks like scattered dots when cross-cut but as streaks when board-cut. So, it is usually best to board-cut palm wood into thicker, ¼” slabs and then to grind high domes on the cabs so that streaks will show in the middle and dots will show along the outside. The root ball of palm trees is oval shaped on the


S TUDY ING THE PA S T OF PE TRIFIE D WOOD

Petrified sycamore should be quarter-sawn, like this cab, so its rays appear in the distinctive and attractive ray fleck pattern.

(Left) This board-cut opalized conifer (Sequoia) shows its growth rings as repeating, oval patterns. (Middle) When a chunk of petrified wood has prominent growth rings, like this oak, cross-cut it so its growth rings show as curving parallel lines that contrast with the agate vein. (Right) This cross-cut petrified oak cab shows its rays flaring outward, because it was cut where the branch forked.

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S TUDY ING THE PA S T OF PE TRIFIE D WOOD

(Left) The lower drawing shows a cross-cut branch with its rays radiating out from its pith, but stopping abruptly where its bark begins. The upper “blow up,” in higher magnification, shows that the bark’s woody structures run perpendicular to the branch’s rays. (Right) This log’s end was “cross-cut” – cut perpendicular to its length – and so shows its annual growth rings as concentric circles, while its rays look like spokes on a wheel. The board on the left was “quarter sawn” – cut parallel to a ray and through the log’s pith – and so shows its rays as regular, interrupted, lines (“ray fleck”). On the right is a “board-cut” board –a cut parallel to the length of the log without going through the pith -- and so shows growth rings as oval, or “V” or “U” shaped patterns. MUHIKHWANNUR W/ FIVERR.COM

outside; inside, there is a mass of larger and smaller rootlets, often passing through each other. If you slab out a petrified palm root at an angle to the larger, oval rootlets, they will look elliptical, like little space ships, as is shown on the bolo tie stone pictured nearby. When petrified wood is entirely or nearly black, including some specimens from Wyoming’s Blue Forest and a lot from Oregon’s southern coast, you can bring out the rays and growth rings in white by soaking the wood in household bleach for a day or two. Be sure to do this after the final grind on a cab but before using a polishing compound. Woody patterns in white on a black background are attractive, as pictured nearby. Other woody structures that can be incorporated into cabs include knots, the effects of wood rot, and the divergence of rays in bold-ray wood that mark where a limb forked. Both cubic rot and brown rot can entirely consume a limb’s woody structure, but sometimes these result in attractive patterns. Partially hydrolyzed wood can show only swirling wood grain. Brown rot can destroy some parts of a limb that later fills with agate but leave small patches of woody material that are striking in contrast to the surrounding agate. Another variable in deciding how to cut petrified wood is the presence of agate veins, which are fairly common

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because when wood dries out, it can crack (“desiccation” cracks). Usually these voids eventually fill with water-borne silica that precipitates as translucent agate, in stark contrast to adjoining, opaque, formerly organic structures. So, with ring porous or bold-ray wood with medium-sized agate veins, cross cuts are best because the rings and/or rays provide a repetitive background pattern to the agate vein, as shown on a cab pictured nearby. Board cuts that show growth rings in a broad, wavy pattern, in contrast, offer a much less striking background for agate veins. Water-borne silica will fill heartwood before voids because silica adheres to surfaces. While voids have only a few surfaces, heartwood consists of masses of wood cells with a great multitude of surfaces. With regard to the petrification process, it has often been said that silica “replaces” wood to form petrified wood. But this is not so, because short mineral molecules cannot replace long hydrocarbon chains of organic molecules. The actual process is “replication,” whereby silica replicates wood at the cellular level, adhering to the outside of wood cells. When grinding petrified wood, super glue is often needed, much more so then when grinding jasper or agate, because petrified wood can have voids caused by insect burrows, heart rot, vessel rot, or desiccation cracks that


S TUDY ING THE PA S T OF PE TRIFIE D WOOD

This bleached, cross-cut petrified conifer shows nearly parallel growth rings; before bleaching it was all black.

This petrified wood from Hampton Butte, Oregon was so highly hydrolyzed that its only remaining woody structures are wood strands in wavy patterns.

When board-cut, petrified palm shows its vascular bundles as vertical streaks.

(Left) Highly colorful petrified wood with agate veins, like this cross-cut bolo stone of Roxy Ann wood from southern Oregon, will make attractive cabs, whichever direction it is cut. (Middle) Petrified sycamore should be quarter-sawn, like this bolo stone, so its rays appear in this distinctive and attractive ray fleck pattern. (Right) Highly colorful petrified wood with agate veins, like this board-cut bolo stone of Roxy Ann wood from southern Oregon, will make attractive cabs, whichever direction it is cut.

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S TUDY ING THE PA S T OF PE TRIFIE D WOOD have not filled with silica. When working on cabs or bolo tie stones, medium-thin super glue can both fill small voids and prevent them from expanding. Spraying an “accelerant” on wet glue, of course, hastens hardening. When working on big slabs or when sculpting larger pieces of petrified wood, experienced lapidaries save the dust and tiny pieces of stone that come off during grinding, pound this material into a dust-like mixture, sift it to remove larger pieces, put the dust into small voids in the wood, and then pour in some highly liquid super glue. Expert lapidaries will usually do this over and over for each grit sequence. (Reasonably priced pints of Starbond superglue and accelerants are available at CCH International.)

LABELING ADDS INTEREST Learning that a pendant is made of petrified wood usually sparks interest: “You mean this rock used to be part of a living tree?” How much more interesting would it be to include a label with such a pendant, as shown on this page, saying: Your pendant is both a fossil and a semiprecious gemstone: it is petrified wood from the Stinkingwater Mountains of eastern Oregon. Your stone is well enough preserved to identify as coming from an oak tree; and, according to geologists, your stone was part of a living tree a very long time ago in the mid Miocene. Note the zig-zig white line, where a crack in the wood was later filled with water-borne silica that turned to agate. While your stone is harder than steel, it is also brittle, so please don’t drop it on a hard surface.” And if you don’t know what variety of tree the stone came from, your label could point out that the pendant’s curved lines mark a tree’s annual growth rings, or that vertical lines mark rays that carried nutrients inside the tree, or that agate veins mark former desiccation cracks. (For an attractive package, put pendants and their labels inside black velveteen bags with drawstring, which are available in bulk from U-Line in size 3” X 4.”) In describing woody features, though, be cautious about saying there is bark on the outside because bark is rare. Bark lacks lignin, the most durable component of wood, and so is easily abraded away when a limb is tumbled downhill by water or by a turbulent, volcanic mudslide (“lahar”). While I’ve collected and identified thousands of specimens of petrified wood from Oregon’s Rogue Valley, I’ve yet to find petrified bark there. Petrified bark is somewhat common where branches were lying in water when volcanic ash rained down on them and resulted in petrification. Try Wyoming’s Blue Forest and Big Sandy Reservoir collecting areas, and you’ll have a reasonably good chance of finding specimens with bark.

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Bark is readily identifiable when viewed with a 20X lens because its woody structure is not aligned with the rays and growth rings of the limb it encloses. The nearby drawing shows bark attached to an extinct pepperwood (Schinoxylon) branch from Wyoming’s Blue Forest collecting area, as viewed in cross section at 20X. Learning to identify petrified wood can be challenging. The first step is to buy a 20X lens. Ten years ago, the standard was a 20X Bausch & Lomb, Hastings triplet, which worked well for me only in bright sunlight or next to a 100-watt bulb. A 20X Hastings triplet now costs $35 or more, while a comparable high-power lens with a built-in LED lens costs less than $10 and can be used in all light conditions. (My “60X Currency Detecting Microscope” with LED lights works well, and it doesn’t matter that the highest magnification is closer to 20X than 60X.) The next step for identifying temperate climate petrified wood is to buy R. Bruce Hoadley’s Identifying Wood: Accurate Results with Simple Tools, which includes magnified photos of the vascular structures of most U. S. commercial timber varieties. Hoadley wrote about living wood for carpenters, but his wood descriptions and micro-photos apply as well to temperate-climate petrified wood, other than for color and smell. (Petrified wood colors are caused by different mineral ions in the groundwater that are carried into the wood; for example, oxidized iron results in reds and yellows.)

TIPS FOR DISTINGUISHING SPECIES Petrified wood, like living wood, is identified by genus and species. The scientific name for red oak is Quercus rubus, where Quercus (oak) is the genus and rubus (red) is the species. Identifying petrified wood species is only for paleobotanists, because this requires cutting thin sections of petrified wood one to two cells thick from three different angles and then studying individual cells under high magnification. It is possible, however, to identify the genus of many conifers and hardwoods by comparing a tree’s vascular system in cross–section at 20X with the microphotos in Hoadly’s book. It is easy to distinguish conifers from hardwoods. Conifers move water through masses of long, tiny tracheids, while hardwoods move water through pores that are much larger, very much larger, than tracheids. Remember, though, that much petrified wood is only well enough preserved to identify in a few areas on each piece, and with petrified round branches, the best preservation is usually found on or near the outside because this was the first part to petrify. Some varieties of hardwoods and conifers are easy to identify because of their distinctive vascular structures.


S TUDY ING THE PA S T OF PE TRIFIE D WOOD

This cross-cut petrified hardwood (Schinoxylon, a/k/a “pepperwood”) shows a continuous dark band of bark separated from the branch by white agate. (This branch was lying in a lake when it began to petrify; then dried out when the lake receded, resulting in the branch and bark separating; then, when again covered with water, the branch and bark petrified. Finally, waterborne silica filled the void between bark and limb with white agate.)

Conifers with resin canals (that move pitch) – including pine, Douglas fir, and spruce – are the easiest conifers to identify because these relatively large resin canals as seen at 20X stand out like small holes torn in a window screen. Ring porous hardwoods – including elm, locust, hickory, and deciduous oak – are the easiest hardwoods to identify because their early-wood vessels are large and arranged in distinctive patterns. (See the nearby drawing of an evergreen oak viewed in cross section at 20X.) With further study, you’ll soon be distinguishing hardwood genera based on the width of rays, the relative size of pores and rays, how many pores appear between a pair of rays, etc. And, with conifers, you’ll be studying their “texture,” a measure of the relative size of tracheids, from the smallest in yews to the largest in Sequoias Paleobotanist Walt Wright, the leading expert in 20X identification, teaches two- to three-day intensive seminars on petrified wood, sometimes followed by a field trip; his seminars have been held in different parts of the country and have cost $100 per person. If you continue to learn more about petrified wood identification, you owe it to yourself to attend some of Walt’s memorable seminars. For more information, email walt.wright@rocketmail.com . An alternative way to start would be to take a local introductory class on petrified wood identification. In early June, I offer a two-day seminar on Oregon petrified wood identification through the Crater Rock Museum in Central Point, Oregon. In these classes, students get to study specimens in hand with their own 20X lenses. Museums

and/or rock clubs near you may offer similar classes. Additional helpful background research would be to contact the federal or state land management agencies nearest your favorite collecting areas to learn if there have been any scientific studies of petrified wood there that list the most common varieties of petrified trees. Included in my published study of the petrified wood from Oregon’s Rogue Valley, based on 1,900 identified specimens, are tallies of the most to least common varieties of petrified wood from six different collecting sites, ranging in age from the early Eocene to the early Miocene. If there are similar studies for your collecting areas, learn the two or three most common varieties of petrified wood present at each. Then, when you find a new piece of petrified wood, compare it first to microphotos of the most common wood varieties found there. Many of the suggestions offered in this article also apply when buying slabs of petrified wood to cut into cabs. Always look for agate veins and for larger agate-filled voids that resulted from wood rot. For cross-cut slabs, select only those that show a distinctive pattern of rays, or growth rings, or both. Look for attractive “ray fleck” in radially-cut sycamore slabs. For all slabs, but especially board-cut slabs that show growth rings as wavy patterns, use a cab template to learn what woody patterns will fit within a cab. And don’t forget to take some dry rags with you: while immersion in water reveals the colors a finished cab will have, it can also conceal cracks. May you share in the joy of cutting and grinding petrified wood and, perhaps, also learn to identify what living tree these beautiful stones came from.

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R&G communit y outlook O FF TH E W H EEL S Erin Dana Balzrette

Ray Pohlkotte Amazing talent, with a wealth of knowledge, all matched with a wonderful sense of humor, makes chatting with Ray truly an honor. Please enjoy “Just Off the Wheels” with Ray Pohlkotte Erin Dana Balzrette: Where is this material found? What drew you to this material? Ray Pohlkotte: This is Cabochon made from Montana agate. It is an alluvial agate found not in one particular place but in the gravels of the Yellowstone River for hundreds of miles. It is well known for having wonderful brown and yellow inclusions which, as is obvious in this particular cabochon, will often form scenes or pictures that are aesthetic to behold.” EDB: What general creative process do you use when creating cabs? RP: I generally make my cabs from pre-cut slabs of material and I wet them to darken the colors and turn them all directions until a shape or design jumps out at me. But even when I have drawn the form I want to cut, I am always open to changing it as the design or pattern in the stone can migrate as you are cutting into it during the doming process, so ultimately I allow the stone to lead me into what I think is the most appealing shape. EDB: What is one bit of advice you’d share with someone considering learning about cabbing? RP: Probably the best advice I could give is to always work with the very best material you can. It might seem intimidating at first, but even though the effort is the same, the reward is much greater - and you will rise to the occasion. I absolutely love the idea of creating something beautiful out of something ordinary, or just in making something that was not there before. EDB: What motivates you to create, and what part of the entire process from finding the rough, to the finished cab is your favorite part of this lapidary process? RP: I enjoy all aspects of this process, from cutting rough into slabs to the final polish - each step involves decisions and creative input, and each has its own rewards.

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WHERE TO FIND RAY POHLKOTTE Company: Magma Karma Studios Facebook: www.facebook.com/MagmaKarmaStudios Facebook Groups: Cabs and Slabs


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TETRAHEDRITE - TENNANTITE

Which is Which?

Crystals of tetrahedrite up to 2.2 cm in size forming a cluster (3.5 × 2.5 × 2.5 cm) with quartz and micro mimetite. Found from Black Pine mine, Granite County, Montana, USA. IVAR LEIDUS, CC BY-SA 4.0, VIA WIKIMEDIA COMMONS

Unassuming, handsome, and confusing minerals STORY BY BOB JONES

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T

he problem with the two common copper sulfosalt minerals, tetrahedrite and tennantite, is their chemistry. Chemically, they are both copper iron sulfides. They are the more common black copper species, and it’s important we treat them separately from the other dark copper species. Tetrahedrite and tennantite use the same elements: copper, iron, zinc, and sulfur to develop molecules on an internal structure. But they differ by incorporating either arsenic or antimony in their chemistry. Each of these metal elements can fit into the atomic structure of either or both these minerals as part of the chemistry of these two sulfides. Theoretically, pure tetrahedrite contains only antimony, while pure tennantite contains only arsenic. To make matters confusing, arsenic and antimony substitute for each other in varying amounts because their electron structure and atom size closely match. In fact, both elements occur in the two species, with one dominating, deciding if the specimen is tennantite or tetrahedrite. To further cause confusion, iron and copper can also substitute for each other, so either can be the dominant metal cation determining the species. As if that is not confusing enough, other metal elements also get into the act including silver, zinc, and mercury in trace amounts — no wonder these two copper species are so daunting. Both species develop crystals in the isometric system, so that’s no guide to distinguishing one from another, making identification difficult. Tetrahedrite has one feature that sometimes helps. It is often very lustrous, while tennantite usually borders on dull, but that is not much help. Additionally, both species can occur in the same ore deposit. Both minerals can occur as important ores of copper but are usually only a small fraction of final production, as other copper minerals tend to be more abundant. In some cases, their silver content is significant. The tetrahedrite from the Yaogangxian mine in China is reported to be silver-rich. You may already realize the two minerals form a series. Tetrahedrite, the copper iron antimony sulfide, is theoretically at one pure end with tennantite, the copper iron arsenic sulfide in pure form at the other end of the series. But allnatural specimens are somewhere between the pure forms. Over the last few decades, geological and mineralogical research has answered many of the mysteries how ore deposits develop. The discovery of countless super hot hydrothermal springs called black smokers along the plate boundaries of the earth’s crust under the oceans and seas explains why many rich sulfide ores are found in chimneylike and thick blanket-like deposits. These unusual hot springs form as waters penetrate the rocks of the crust, gaining more and more heat and dissolving more metals as they travel. As continental plates move inexorably against each other, this mineral-rich water that is under pressure gets hotter and hotter, dissolving more and more metals. The waters follow cracks, joints, and faults, surging toward the earth’s surface. As the waters encounter the cooler crustal

Chalcopyrite on tetrahedrite-sphalerite from Russia. JAMES ST. JOHN, CC BY 2.0, VIA WIKIMEDIA COMMONS

This group of tennantite xls show their typical tetrahedron shape and are from Tsumeb, Namibia. KRISTALLE

The Heroodfoot mine, Liskeard, Cornwall England produced upern tetrahedrite crystals coated with chalcopyrite. BIDDEAUX COLLECTION

rocks, they deposit their minerals in veins and joints. The remaining waters, still mineral-rich, burst forth into the cool ocean waters and abruptly drop their remaining mineral load. This function accounts for many major ore deposits composed of sulfide minerals formed millions of years ago. In my collecting trips into Mexico, I’ve noted that many of the mines I’ve visited - Fresnillo, San Martin, Niaca, and others - line up in a more or less straight line north to south in that silver-rich country. I can’t help but suspect those deposits were formed along old crustal faults long since uplifted to form the present land. All these deposits are rich in the sulfides pyrite, chalcopyrite, galena (including tenantite, tetrahedrite, and silver minerals) and present as blanket-like layers with chimney off-shoots rich in metal

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Tetrahedrite - Tennantite: Which is Which

The Sweet Home mine, Alma, Colorado produced amazing rhodochrosites some with associated bright tetrahedrite crystals as seen on this specimen. COLLECTORS EDGE

Tennantite - Tsumeb Mine (Oshikoto) Region, Namibia (7x7cm) DIDIER DESCOUENS, CC BY-SA 3.0, VIA WIKIMEDIA COMMONS

ores. Gangue minerals like calcite, dolomite, siderite, barite, quartz, and fluorite are also found with the sulfides. The surging hydrothermal solutions contain various metal elements; this accounts for the presence of silver, mercury, and other trace elements in developing crystals of tetrahedrite and tennantite. It’s no wonder these two species contain both arsenic and antimony. In some cases, there are one or two minor but important differences between tetrahedrite and tennantite, which helps distinguish between them, luster being one. Tetrahedrite crystals tend to be very smooth faced and lustrous while tennantite is less so. Another odd distinguishing feature is that brassy chalcopyrite seems to have an affinity for tetrahedrite, so it often coats tetrahedrite crystals with a brassy look. As you have probably guessed, tetrahedrite gets its name

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from its crystal form; the tetrahedron is a shape that looks like a pyramid with one corner of the pyramid pulled out to distort or stretch the triangular faces. Tennantite is named for British scientist Smithson Tenant. Initially, tennantite was well known in the early silver mines of Germany and elsewhere but not recognized by that name. In fact, every black to gray sulfide mineral with tetrahedron crystals was called tennantite. There was no tetrahedrite as such! It wasn’t until 1819 that tennantite was formally identified as a valid mineral; and, in 1845, a scientist did more studies on the minerals and distinguished between them — making tetrahedrite a separate mineral. Switching gears a bit, there is a large group of unusual sulfides called sulfosalts. The sulfosalt group, in general terms, have three main chemical or elemental components in the group’s minerals and are given the letters A, B, and S. A is any one of a dozen metals that serve as cations; B is any one of a half dozen semi-metals in the composition; and S is the sulfide anion member. Members of the group form at fairly low temperature and are often rich in silver. Sulfosalts include such noteworthy species as proustite and pyrargyrite, two exceedingly rich silver species that are colorful and far more eagerly sought than our two black copper iron sulfides. Other available and very handsome sulfosalts, which collectors are eager to own, include bournonite, enargite, and rare gratonite. Enargite was a major ore at Butte, Montana, but not common in most copper deposits. Gratonite is quite rare and seldom found. Bournonite is found in quantities of collectible specimens in China, Cornwall, England and Bolivia. Tetrahedrite and tennantite are among the more common of the sulfosalts, so they are available to collectors but not as costly as proustite, pyrargyrite, and bournonite. Our two copper iron sulfides have been found in a large number of ore deposits and readily available for decades. As mentioned, tetrahedrite and tennantite crystals form in low- to medium-temperature ore deposits, but one major exception to this is the copper mine of Cornwall, England. This deposit contains a host of minerals like cassiterite, formed in the high-temperature range, well above the normal environment where we usually find tennantite and tetrahedrite. Yet, both are found in Cornwall. As mentioned, tennantite was the first of these two to be identified. It was encountered during silver mining in several deposits in Germany and was given several names depending on the metals it yielded during smelting. The chemistry applied to the mineral in Cornwall showed it was an argentum, arsenic, cupro, ferro mineral, so the elements it gave up when smelted were silver, arsenic, copper, and iron. Thank goodness, two Phillips brothers in England identified it in 1817 from the mines of Cornwall and named it tennantite for scientist Smithson Tennant.


Tetrahedrite - Tennantite: Which is Which In the U.S., the nicest tetrahedrite came from the big copper mine at Bingham, Salt Lake County, Utah. Crystals averaged about a half-inch on an edge and had a fairly bright luster. In Mexico, Mina Bonanza of Zacatecas produced fine black lustrous tetrahedrite crystals approaching an inch. These often had a grayish coating that might be tennantite. They occurred with other sulfosalts, including fine bournonite. Even though they lack high luster, they proved to be tetrahedrite! The mines of Germany produced the very best tetrahedrite crystals to an inch or more. The finest specimens have sharp tetrahedron crystals coated with bright brassy chalcopyrite that rival the Cornish specimens of chalcopyrite coated tetrahedrite from the Heroodsfood mine, Liskeard, better known for its amazing bournonite. The chalcopyrite-coated tetrahedrite from Cornwall and Germany are considered classics and are eagerly sought. Several of the metallic ore mines of Peru, high in the Andes Mountains, have also yielded wonderful tetrahedrite and tennantite. Mines in the Ancash District produce crystals to an inch on an edge. The Casapalca mine, Lima Department, is the source of the largest tetrahedrite crystals, with a few reported to approach five inches. Though some of the Peruvian crystals are of excellent size, they do not hold the record for crystal size for tetrahedrite. That honor goes to a couple of older small French

The classic mine at Tsumeb, Namibia produced wonderful tennantite. This is a superb example of tennantite pseudomorph after azurite from that mine. BOB JONES

Tennantite; Bureau of Mines, Mineral Specimens. PUBLIC DOMAIN, WIKIMEDIA COMMONS

metal mines few collectors have heard of, as they did not produce specimens in quantity. When I was at the Pierre and Marie Curie Museum in Sorbonne, France, curator Pierre Bariand pulled out a tetrahedrite crystal that was a perfect tetrahedron with slightly modified faces. It was textbook perfect and was nearly six inches across. The faces were not bright and had lightly colored blotches of green and yellow chalcopyrite on the surfaces. This was an example of just a few of the large crystals that had been found during a brief mining period at Irazein, Ariege Department, France. For pseudomorph collectors, a source of tennantite has on occasion been Tsumeb, Namibia. Here it has been found in fine crystals and also as a replacement for azurite. These specimens are dull and rough-surfaced but very interesting. With many metal ore deposits long since depleted, the supply of these two copper sulfosalts in the mineral market is limited. Specimens from old collections do appear from time to time and should be considered for your collection. The potential for a good tetrahedrite is more possible now, since there is a strong flow of minerals from China. The Yaogangxian mine, better known for fluorite, scheelite, ferberite, and bournonite has also produced fine tetrahedrite rich in silver. As you well know, this writer recognizes that black to gray minerals, particularly the copper sulfides, are not as popular or as frequently displayed at shows as they deserve. After all, they have curious chemistry, interesting crystal forms, are sulfosalts that are well worth collecting as a group, and add another attractive dimension to your collection. Good examples of tetrahedrite and tennantite are very attractive and are found in well-crystallized clusters that exhibit nicely. Collecting them encourages you to look into their chemistry. Any wide-ranging collection should have more than a showy facade of minerals. It should include these two fascinating black to gray copper species with an interesting chemistry and crystal form.

WWW.ROCKNGEM.COM | JULY 2021 67


ROCK SCIENCE

BY STEVE VOYNICK

Soapstone: Past and Present

I

n appearance, soapstone does not rank among the most attractive stone-carving mediums. Opaque and most often a dull, grayishgreen color, it lacks the eye-catching brilliance of white marble or the soft glow of translucent alabaster. Yet soapstone has a long and interesting history as one of the first stones ever quarried and the eminently workable of all stone-carving mediums. Also called steatite, soapstone is a metamorphic rock consisting of talc and lesser amounts of chlorite, carbonate, amphibole, and pyroxene minerals. Relatively abundant and widely distributed, soapstone forms at convergent plate boundaries where subducted sections of crust are subjected to high levels of heat and pressure. It is also found in highly metamorphosed mountain regions. Such ultramafic (low-silica, high-magnesium) rocks as peridotite, dunnite, and serpentinite typically metamorphose into soapstone.

Soapstone consists largely of talc and is the most workable of all stone-carving mediums. WIKIMEDIA COMMONS

Soapstone contains between 30 and 80 percent talc [basic magnesium silicate, Mg3Si4O10(OH)2]. Crystallizing in the monoclinic system, talc usually occurs in compact masses; it is translucent to opaque and has a pearly luster. Traces of iron impart grayishgreen colors to most soapstone; other impurities create brown, yellow, and gray hues. At Mohs 1.0, talc is the softest of all minerals. With a specific gravity of 2.75, it is slightly denser than quartz. Its phyllosilicate structure consists of stacks of flat, very weakly bound

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tetrahedral sheets. The slightest physical force—even scratching with a fingernail—overcomes talc’s weak atomic bonding to account for its softness and soap-like feel. Talc imparts varying degrees of softness and “soapiness” to soapstone. Containing between 30 and 70 percent talc, low-grade soapstone has a Mohs hardness of 2.5-3.0. Higher grades, which contain as much as 90 percent talc, have a Mohs hardness of 1.5. Along with its softness and great workability, soapstone is also nonporous, nonconductive, and resistant to heat, acids, and alkalis. Systematically quarried for at least 10,000 years, soapstone was likely the first rock ever carved by late Paleolithic sculptors. By 7500 BCE, Inuit artisans in Alaska were carving soapstone amulets and ceremonial objects, a tradition that survives today in the Inuit carvings of seals, bears, and other regional wildlife that are the iconic Alaskan souvenirs. However, some of these carvings, although labeled as soapstone, are actually fashioned from look-alike argillite-, serpentine-, and chlorite-group rocks. By 5000 BCE, California’s Tongya people were quarrying soapstone on Santa Catalina Island and fashioning bowls for trade with the mainland. Many other Native American groups produced soapstone pendants, beads, figurines, bowls, and cooking slabs. Ancient Egyptian scarabs that served as amulets and impression seals most often consist of carved soapstone glazed with faience. By 900 CE, soapstone pots and bowls had become a major trading commodity for the Vikings. The harder, low grades of soapstone have architectural uses. The Nidaros Cathedral in Trondheim, Norway, built between 1070 and 1300 CE, consists entirely of soapstone. The nearby Bakkaunet Quarry, the world’s largest underground soapstone mine, provided the cathedral’s 10,000 cubic

The Nidaros Cathedral in Trondheim, Norway, built between 1070 and 1300 CE, consists entirely of soapstone. WIKIMEDIA COMMONS

meters of soapstone. And in Brazil, the exterior of Rio de Janeiro’s iconic, 98-foot-high Christ the Redeemer sculpture consists of soapstone panels. In the early 1900s, nonconductive soapstone was standard in electrical control panels, switch-box and transformer housings, and insulators. Today, Brazil and India mass-manufacture soapstone jewelry boxes, goblets, coasters, dinner plates, vases, and figurines for worldwide export. But most soapstone is made into floor, shower, and cooking tiles, and heat-resistant, nonabsorbent countertops for kitchens and laboratories. Today’s annual soapstone production is uncertain. Most high-grade soapstone is crushed and milled to recover talc. The production of lower-grade material mined for architectural and commercial uses in such major soapstone-producing nations as India, Brazil, and China is often undocumented. Although soapstone, as a carving medium, will never be in the same league as marble or alabaster, it nevertheless deserves respect. After all, it was the medium used by many great stone carvers, past and present, to develop their skills. Steve Voynick is a science writer, mineral collector, and former hardrock miner, and the author of guidebooks like Colorado Rockhounding and New Mexico Rockhounding.


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WWW.ROCKNGEM.COM | JULY 2021 69


SNEAK PEEK

Grand and Glorious Gemstones What’s not to love about gemstones? They glisten, they shimmer, they have striking edges and exquisite faces, and they make a wonderful addition to any collection. For these reasons, and many others, we’ve created the Glorious Gemstones digital series. The second of the three-part series just became available and can be accessed FOR FREE at the Rock & Gem website. Here’s a sneak peek at some of the many unique and exceptional gemstones handselected by some of the Glorious Gemstones sponsors. Enjoy!

ARKENSTONE GALLERY OF FINE MINERALS A pioneer of the online mineral market since the 1990s, this Dallas-based business, led by Dr. Rob Lavinsky, is a continually evolving leader in the industry. 125 carat ametrine gemstone; “The Eye of the Jaguar” gem topaz. Arkenstone Gallery of Fine Minerals, www.irocks.com

DIG MAINE GEMS DMG is a family-run and firstof-its-kind rockhounding business specifically geared toward teaching people about the basics of Maine’s rockhounding and minerology. Faceted green tourmaline gemstone; amethyst cut crystal. Dig Maine Gems, www.digmainegems.com

BESTINGEMS.COM A team of passionate and qualified individuals who aim to serve and celebrate the gemstone industry while educating others about gemstone quality and characteristics. Tanzanite round shape gemstone, 8mm; a selection of pendant semi-mounts. BestInGems.com

GET YOUR 38-PAGE FREE COPY OF GLORIOUS GEMSTONES Visit the Rock & Gem website (www.rockngem.com) to learn how to gain access to each digitial issue of Glorious Gemstones upon publication. 70 ROCK&GEM | WWW.ROCKNGEM.COM


SNEAK PEEK

JOSEPH P. STACHURA GEMSTONES & PEARLS A graduate gemologist-run diversified wholesale supplier of fine gemstones, pearls, beads, jewelry, tools,carvings, findings, and other products in business since 1955. Jadeite dragon belt buckle; strands of Akoya pearls. Joseph P. Stachura Gemstones & Pearls, www.stachurawholesalegemstones.com/

ASTRO GALLERY OF GEMS Serving the gemstone, mineral and fossil interests of a range of clients since 1961, the home gallery, Fifth Avenue in New York City, New York, is the largest gem and mineral gallery - with a 12,000 square foot showroom. Plus, a newly established additional Astro Gallery of Gems locality in Meridian, Idaho. Hydrothermal Aquamarine Crystal; Stibnite From Wunning Mine, Jiangxi Province, China. Astro Gallery of Gems, www.astrogallery.com

FAZMAGORIC TREAZURES With the mission of sharing the beauty of Mother Earth with the world, Fazmagoric Treazures offers gemstones, minerals, crystals, fossils, and related items of home décor and jewelry. Sodalite alien featuring tiger stone eyes; showcase collection of black amethyst and pink amethyst. Fazmagoric Treazures, www.etsy.com/shop/FazmagoricTreazures

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WWW.ROCKNGEM.COM | JULY 2021 71


Show Dates

TO VIEW LATER CALENDAR DATES VISIT OUR SITE AT ROCKNGEM.COM.

JUNE 2021 18-20—REEDSPORT, OREGON: Annual show; Lower Umpqua

Gem and Lapidary Society; Reedsport Community Building, 451 Winchester Avenue; Fri. 10-5, Sat. 9-5, Sun. 10-4; Free admission; Dealers offering various rocks, gems, minerals, lapidary, with exhibits and demonstrations, and activities for children, including a complimentary rock to the first 300 children to attend the show Friday (11am-2pm) and Saturday (10am2pm); contact Bambi Darling, 100 River Bend Road Sp. 68, Reedsport, OR 97467, (541) 420-8014; Email: reedsportrockshow@gmail.com; Website: https://www.facebook.com/pg/ Lower-Umpqua-Gem-Lapidary-Society-1579099422193547 18-20—BIG PINEY, WYOMING: Annual show; Sublette County

Rock Hounds; Sublette County Fairgrounds, 10937 Highway 189; Fri. 9-5, Sat. 9-5, Sun. 9-4; Adults $2, free admission for children; The annual Sublette County Rock Hound's Gem & Mineral Show 2021 is host to the American Federation of Mineralogical Societies and the Rocky Mountain Federation of Mineralogical Societies 2021 conventions. View dealers, demonstrations, exhibits, and enjoy field trips and food concessions.; contact Jim Gray; Email: jimgray@wyoming.com; Website: https://rmfms.org/index.php?page=events-clubshows 18-20—ARDEN, NORTH CAROLINA: Annual show; MAGMA, Jacquot & Son Mining; Camp Stephens, 263 Clayton Road; Fri. 9-6, Sat. 9-6, Sun. 10-4; free admission; 13th annual gem, mineral and fossil show; dozens of vendors offering gems, minerals, fossils, rocks, artifacts, and meteorites, among other items; contact Richard Jacquot, PO Box 542, LEICESTER, NC 28748, (828) 779-4501; Email: rick@wncrocks.com; Website: www.AmericanRockhound. com 19-20—MILACA, MINNESOTA: Annual show; Dale's Rocks & More; Hairy Mosquito Trading Co, 21287 Highway 169; Sat. 9-5, Sun. 9-5; free admission; Over 40 vendors and artisans set up in an outdoor park-like setting offering everything from rocks and gems to handmade creations, with COVID precautions in effect; contact Dale Fure, MN 55330; Email: dalesrocks_more@outlook.com 19-20—GASTONIA, NORTH CAROLINA: Annual show; Gaston Gem, Mineral and Faceters Club; Johan Newcombe Event Center /Habitat for Humanity Bldg., 1840 E. Franklin Blvd; Fri. 10-6, Sat. 10-4; FREE; Recharge, relax and indulge that "Oooo,shiney" gene! Our vendors are offering the best in mineral specimens, gems, jewelry and fossils. Sluice on site with treasure buckets; contact Bob Winstanley, (704) 577-3391; Email: machine66man@gmail.com; Website: www.gastongemclub.weebly.com 19-20—GRAPEVINE, TEXAS: Annual show; Arlington Gem and Mineral Club; Grapevine Convention Center, 1209 S Main St.; Sat. 9-6, Sun. 10-5; Adults $8, seniors and children (3-15) $7, free admission for military personnel with ID and scouts in uniform; contact Rick Allen - Show Chairman, (817) 528-475; Email: rickallen57@ sbcglobal.net; Website: www.agmc57.org 26-26—KENT, CONNETICUT: Annual show; Danbury Mineralogical Society and the Connecticut Museum of Mining; Connecticut Antique Machinery Museum Campus, 31 KentCornwall Road; Sat. 9-4; free admission; Show will take place rain or shine, new vendors welcome; contact John Pawloski, P.O. Box 425, Kent, CT 06757, (860) 927-0050; Email: j.a.pawloski@att.net; Website: www.ctamachinery.com

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26-27—BUTTE, MONTANA: Annual show; Butte Mineral and Gem Club; Butte Civic Center Annex, 1340 HARRISON AVENUE; Sat. 10-5, Sun. 10-4; Adults $3, free admission for children; contact Pete Knudsen, 1301 West Gold Street, Butte, MT 59701, (406) 4905828; Email: pknudsen@mtech.edu

JULY 2021 9-11—CASPER , WYOMING: Annual show; Natrona County Rockhounds; Ramkota Hotel, 800 N Poplar St.; Fri. 9-5, Sat. 9-5, Sun. 9-4; Adults $3, and free admission for children under 12; The Natrona County Rockhounds annual gem and mineral show will also serve as host for the annual show of the Wyoming State Mineral & Gem Society. Vendors will be selling rocks, minerals, fossils, jewelry, and lapidary supplies; demonstrations, displays, and exhibits will be present, and there will be activities for children; contact Mac Goss; Email: macogre13@yahoo.com; Website: https://www.facebook. com/groups/123048541068947/ 9-11—DURANGO, COLORADO: Annual show; 67th Annual Four Corners Gem and Mineral Show; Four Corners Gem and Mineral Club; La Plata County Fairgrounds, 2500 Main Ave; Fri. 10-6, Sat. 10-6, Sun. 10-4; $3; Vendors selling rocks, gems, minerals, fossils, crystals, geodes, meteorites, beads, jewelry, findings equipment; educational displays; mini-workshops; and activities for children ; contact Jama Crawford; Email: info@durangorocks.org; Website: http://www.durangorocks.org/gem-show.html 10-10—WEST ALLIS, WISCONSIN: Show and sale; Wisconsin Geological Society; Mother of Perpetual Help Parking Lot, 1121 S 116th St, Parking on 117th st side; Sat. 10-4; Free to the public; Outdoor show/swap, Rocks, Minerals, Crystals, Jewelry, Fossils.; contact Pierre Couture, 1001 S 97th St, West Allis, WI 53214, (414) 704-2954; Email: pierre.couture007@gmail.com; Website: Pierre Couture 16-17—MINOCQUA, WISCONSIN: Annual show; Lakeland Gem and Mineral Club; Lakeland Union High School , 9573 State Hwy 70 Minocqua, WI; Fri. 10-6, Sat. 9-5; free admission; 53rd annual show, vendors offering a wide variety; demonstrations; several geologists will be onsite to help with identification of rocks and minerals; auctions; popular activities for children including the kids store; contact Pattie Hartmann, (715) 477-2519; Email: gypsy1120@coslink.net; Website: facebook lakeland gem and mineral club 16-18—FRISCO , TEXAS: Annual show; Texas Mineral and Fossil Dallas/Frisco Show; Embassy Suites by Hilton Dallas Frisco Hotel Convention Center & Spa, 7600 John Q Hammons Dr,; Fri. 10-6, Sat. 10-6, Sun. 10-4; Free admission ; Retail / wholesale dealers - minerals, fossils, meteorites, jewelry. ; contact Sandra Gonzales, Denver, CO 80222, (720) 425-3948; Email: info@rockygems.com; Website: www.rmgmpromotions.com 17-18—TULSA, OKLAHOMA: Annual show; Tulsa Rock and Mineral Society; Tulsa Fairgrounds-Exchange Center, 4145 E. 21st St.; Sat. 9-5, Sun. 10-5; Adults $6, free admission for children, scouts in uniform, and police, fire, and military with ID; Vendors offering rocks, minerals, jewelry, fossils, a fluorescent display, demonstrations, and activities for children ; contact Martha Rongey, 612 W. 120th St. S., Jenks, OK 74037, (918) 230-1094; Email: m_rongey@sbcglobal.net; Website: www.tulsarockandmineralsociety.org 17-18—MOOSE LAKE, MINNESOTA: Annual show; Carlton County Gem & Mineral Club; Riverside Arena, 20 Earl Ellens Drive; Sat. 9-5, Sun. 9-3; free admission; Current COVID-19 mandates will be followed — masks will be mandatory; contact David Johnson,


TO VIEW LATER CALENDAR DATES VISIT OUR SITE AT ROCKNGEM.COM.

2815 E 4th St, Superior, WI 54880, (218) 591-7725; Email: davidrj@ chartermi.net; Website: www.superiorlapidary.com 21-25—FRANKLIN, NORTH CAROLINA: Annual show; Echo Valley Gem Show; Echo Valley Showplace, 6456 Sylva Rd (across from GLW), 6456 Sylva Rd (across from GLW); Wed. 9-6, Thu. 9-6, Fri. 9-6, Sat. 9-6; Free admission; Dealers from around the world selling minerals, crystals, gems, rough rock, cabochons, slabs, beads, jewelry Sun 9-4pm; contact Damian; Email: mbellpoint@ gmail.com; Website: www.bellpointpromotions.com 22-25—FAIRPLAY, COLORADO: Show and sale; Jay Penn; Fairplay River Park Event Site , 200 Platte Dr, ; Thu. 9-5, Fri. 9-5, Sat. 9-5, Sun. 9-5; free admission; 24 Dealers at this OUTDOOR show, offering mineral specimens, rough, slab, jewelry, and cabochons; contact Jay Penn, 200 Platte Drive, Fairplay, CO, CO 80440, (150) 588-34195; Email: jaypenn246@gmail.com; Website: http:// abqfallshow.wix.com/fairplay 23-25—FRANKLIN, NORTH CAROLINA: Show and sale; Gem & Mineral Society of Franklin, NC; Robert C. Carpenter Community Building, 1288 Georgia Road; Fri. 10-6, Sat. 10-6, Sun. 10-4; Adults $3, free admission for children 12 and under; Dealers from across the U.S., offering a great selection of rough and cut gemstones, gold and silver jewelry, minerals, beads, findings, lapidary equipment, and repairs; contact Linda Harbuck, 98 Hyatt Road, Franklin, NC 28734, (828) 524-3161; Email: lindah@franklin-chamber.com; Website: www.visitfranklinnc.com 23-25—TENINO, WASHINGTON: Annual show; Washington Agate and Mineral Society; Tenino City Park, On Park Avenue; Fri. 9-6, Sat. 9-6, Sun. 9-5; free admission; Rock and gem show is held during Oregon Trail Days; contact Daniel De Boer; Email: keylock1@ live,com; Website: https://wamsolympia.wordpress.com 24-25—ERIE, PENNSYLVANIA: Show and sale; Gem City Rock & Mineral Society; ZEM ZEM Shriners Banquet & Conference Center, 2525 West 38th St; Sat. 10-6, Sun. 10-5; Adults $4, seniors $3.50, free admission for children under 12 and scouts in uniform; Dealers offering crystals, gems, fossils, geodes, jewelry beads; demonstrations and displays; activities for children; and admission is based on Federal, State, Local and Conference Center recommendations and mandates for masks, social distance & occupancy at the time of the show & sale; contact Gem City Rock & Mineral Society, Erie, PA; Email: gemcityrockclub@gmail.com

AUGUST 2021 11-11—HANCOCK, MICHIGAN: Annual show; Quincy Mine Hoist Association; Quincy Mine Hoist Association, 49750 US-41; Wed. 10-8; free; This is the quincy mine annual rock swap, which is now an all-day event and held in the large open area in the back of the hoist. This is where all the locals come to bring their finds to sell. They also have a great mine tour which is a must.; contact dale hartmann, 24012 oneco road, calumet, MI 49913, (715) 477-2519; Email: brujodale@coslink.net; Website: https://www.quincymine.com/ 13-15—PUYALLUP, WASHINGTON: Annual show; Puyallup Valley Gem & Mineral Club; Tacoma Sportsmen's Club, 16409 Canyon Road East; daily 10-5; Free admission; Vendors offering finished and rough materials, crystals, fossils, geodes, lapidary equipment, demonstrations, and activities for children; contact Jim Christian, 13814 109th Avenue Court East, Puyallup, WA 98374, (253) 720-9502; Email: jimchristian_205@hotmail.com

Show ShowDates Dates

13-15—PORTLAND, OREGON: Annual show; Mt. Hood Rock Club; Jackson Armory, 6255 NE Cornfoot Road; Fri. 10-5, Sat. 9-5, Sun. 9-3; free admission; Vendors selling: minerals, rocks, beads, jewelry, fossils; demonstrations; displays; and activities for children; contact Wayne King , (503) 284-7195; Email: mhrcdc@gmail.com; Website: www.mthoodrockclub.com 14-15—ARCADIA, CALIFORNIA: Annual show; Pasadena Lapidary Society; Arcadia Masonic Center, 50 W. Duarte Road; Sat. 10-5, Sun. 10-5; Free admission; NEW DATES!! 62nd Annual Tournament of Gems with the theme —Inspiration Unearthed— features vendors selling gems, minerals, fossils and jewelry, with displays, demonstrations, and activities for children; contact Ellen Ferrell, President, c/o PO BOX 5025, Pasadena, CA 91117-0025, (727) 512-0381; Email: Ellenbf2007@aol.com; Website: pasadenalapidary.org 14-15—GONZALES, LOUISIANA: Annual show; Baton Rouge Gem & Mineral Society ; Lamar Dixon Expo Center Trademart Building, 9039 S St. Landry Ave; Sat. 10-5, Sun. 10-5; $5 Adults; $3 Children 5-12; Children 4 and under free; $1 off for Scouts in uniform; Military personnel free with military ; Vendors will be selling rock specimens, fossils, minerals, tools & jewelry. We will be raffling off an Amethyst Cathedral again this year. ; contact Wanda Gawarecki, 5191 Hwy 19, Ethel, LA 70303, (225) 603-3870; Email: mercymom3@gmail.com; Website: www.brgemandmineral.org 20-22—LEBANON, PENNSYLVANIA: Annual show; Mid-Atlantic Gem and Mineral Association; Lebanon Valley Fairgrounds and Expo, 80 Rocherty Road; Fri. 10-6, Sat. 10-6, Sun. 10-4; Adults $6, free admission for children under 12; Mid-Atlantic's 23rd annual premium gem, jewelry, bead, mineral and arts show: Gem Miner's Jubilee; contact Teresa Schwab, PO Box 352, Monrovia, MD 21770, (301) 807-9745; Email: beadware@rcn.com; Website: www.gem-show.com 20-22—RICKREALL, OREGON: Annual show; Willamette Agate and Mineral Society; Polk County Fairgrounds - outdoors, 520 S Pacific Hwy W; Fri. 9-5, Sat. 9-5, Sun. 9-5; free; outdoor show with various vendors; contact Theresa Donley, (503) 930-5115; Email: tkdddt@hotmail.com; Website: www.WAMSI.net 21-22—BOSSIER CITY, LOUISIANA: Annual show; Arklatex Gem & Mineral Society; Bossier Civic Center, 620 Benton Rd., 2009 Chelsy Dr.; Sat. 9-6, Sun. 10-4; $4.00; Aug 21-22 Bossier City, Louisiana: 46th annual show, Ark-La-Tex Gem & Mineral Society, Bossier City Civic Center, Sat 9-6, Sun 10-4. Adults $4.00, Admission is free for Children under 6 & Students with I.D., Custom and unique Jewelry, Beads, Gems and Minerals, Fossils, Educational exhibits and Demon; contact Delwin Glasner, 2009 Chelsy Dr., Benton, LA 71006, (318) 517-7372; Email: dglasner2001@yahoo.com; Website: Delwin Glasner 27-28—CASTLE ROCK, WASHINGTON: 55th Annual Show; Southern Washington Mineralogical Society; Silver Lake Grange, 3104 Spirit Lake Hwy, Exit #49 off I-5; 7 miles up Spirit Lake Hwy; Fri. 10-5, Sat. 10-5; Free; Dealers, member displays, demonstrations, and activities for children ; contact Vicki Johnson, PO Box 704, Longview, WA 98632, (360) 751-8031; Email: vickijrocks@msn.com 28-29—EAST PEORIA, ILLINOIS: Annual show; Geology Section of Peoria Academy of Science; East Side Center, #1 East Side Drive; Sat. 9-5, Sun. 10-5; free admission; 57th Annual Show with dealers, demonstrations, bead making, flint knapping, fluorescent display, and activities for children; contact Jim Travis, 2812 N. Peoria Ave., Peoria, IL 61603, (309) 645-3609; Email: boatnik@aol.com; Website: pasgeology.com

WWW.ROCKNGEM.COM | JULY 2021 73


WHAT TO CUT

BY RUSS KANIUTH

Pink Natrolite

F

or the past year, we haven’t seen many new materials surface in the lapidary marketplace. However, one did and stood out amongst the others. Early on, there were several conflicts as to the name and identification of this material. I heard it called thomsonite and pink larimar, but it turned out to be natrolite after it was thoroughly tested. This particular variation of natrolite comes from Indonesia, where it’s being mined as seam material. It’s botryoidal on one side, attaching to its basalt host stone, and has radial crystals tinted by iron, giving it that pink larimar appearance on the opposite side. Larimar has been an exceedingly popular material for quite some time now. So, as a new type of stone with an equivalent appearance with a pink-rose color, natrolite enjoyed great popularity in a hurry. Pink natrolite is easily found. It was sold at the Quartzite and Tucson shows this year and can also be found online via eBay and Facebook. Most of this material is smaller-sized pieces under a couple of inches in either direction and relatively soft, about 4.5 on the Mohs scale. The one thing to look for when shopping for this material other than the pattern is its thickness. Always look at both sides and make mental notes of whether or not there will be enough material for a cab after the botryoidal backside has been sanding down flat. Since this is a seam material, you won’t have to do any slab cutting. Instead, you’ll have to trim out your preforms and then sand the backside. This material comes quite often in curled pieces, not always flat, so you’ll

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have to make adjustments as to how to trim each preform so that you can get a flat-backed cab. Once you have your preforms cut out and are ready to cab, natrolite is fairly easy to cab. Though it looks like larimar, it’s much softer and doesn’t break apart as larimar does. So, start on an 80 grit steel wheel to shape your cabs, go lightly at first, get a feel for the hardness of the material, and then start doming your cab. Many people like to use 220 “steel” wheels in their setup, but I like to use 140 soft resin diamond wheels before moving on to the 280 grit. It quickly removes deep scratches and takes much of the hard work away so that by the time you are ready to move on to the 280, the majority of your work is already done. At the 280 grit stage, this is where you need to make sure all the scratches are completely gone before moving on. This material can be very difficult to see scratches due to the white coloring and radial crystal patterns, so it’s best to have a good light source in your shop and dry off the cab thoroughly to see if the surface is scratch-free. By the time you finish the 600 grit stage, you’ll notice a nice polish already appearing; it doesn’t take much to get a brilliant mirror polish on natrolite. Continue to the 1200 and up to 14k grit, and from here, you shouldn’t have to go any further, and this should yield a beautifully polished cab. Russ Kaniuth is the owner of Sunset Ridge Lapidary Arts and the founder and operator of the Cabs and Slabs Facebook group. See more of his work at www.sunsetridgelapidary.com.


ROCK & GEM PRESENTS

Glorious Gemstones From the publishers of

Join us in promoting and celebrating gemstones’ wonder and beauty by becoming a sponsor of the new limited-edition print-digital hybrid series, Glorious Gemstones. Each issue of Glorious Gemstones is FREE and will help readers: • Explore the science behind gemstones. • Consider techniques, tools, and sources of inspiration for cutting gemstones and using them to create art and jewelry. • Understand the current market for gemstones. • Learn about some choice mines to dig or tour in search of gemstones.

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ON THE ROCKS

BY BOB JONES

Experiencing Spring Show Season

T

he all-important Tucson mineral event in February 2021 was canceled, but that did not stop many dealers from forging ahead, opening up shop, and doing business in Tucson and to a greater extent on the internet. Using proper safety procedures, some dealers opened their shops and sales locations by appointment during the usual January-February period in Tucson. Because of my age, I had gotten my shots, so I spent a little time in Tucson, primarily in the Mineral City Complex, where several dealers opened. As usual, I saw some really great mineral specimens and had a chance to visit with customers and dealers. They were all positive about returning in April for another period of sales and hopeful that Tucson 2022 will occur. Despite restrictions, travel difficulties, and more, the February events — followed by the much larger active activity 2021 mineral events in Tucson — gave some dealers and collectors a limited but enjoyable experience.

CONNECTING VIRTUALLY The most exciting event that happened for the 2021 Tucson event occurred on the internet. Bluecap Productions organized a series of virtual internet reports about a limited version of “What’s Hot in Tucson” on YouTube. The set-up was a Zoom event, with two weekend events

This set up of the I.C. Mineral Shop is a typical example of the shops in the Mineral City Complex. BOB JONES

run Thursday-Sunday on the weekend before the canceled 2021 Tucson Show days and on the normally scheduled four days of the Tucson Show. Each virtual broadcast was two-and-a-half hours and featured mineral dealers from all over the world. Dealers shared some of the superb minerals they had planned to have in Tucson but could not, and this way, viewers could at least get a flavor of what they were

This superb example of wulfenite from the Rowley mine was on display during my spring 2021 visit to shows. BOB JONES

76 ROCK&GEM | WWW.ROCKNGEM.COM


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On the Rocks

You can always find fine azurite specimens from Milpillas, Mexico at Unique Minerals, Mineral City Complex. BOB JONES

missing. Bluecap also included museum curators who talked about their facilities, and editors introduced what literature was new and planned. Just like a regular “What’s Hot” edition, it was hosted by Peter Megaw and his daughter Lauren, who visited with dealers making informative and insightful observations about the minerals shown. Lauren is an important leader in an emerging group of young mineral collectors who are very serious, knowledgeable, and eager about minerals. The virtual program went beyond individual minerals by having interviews with magazine editors and museum curators who talked about their plans for the future. This multi-part “What’s Hot” was really a worldwide event, as it included not only people in the U.S. but folks from Europe and Australia on camera as well. I even did a bit of hosting when I interviewed my son Evan, co-partner of Unique Minerals, about some of their fine minerals.

“WHAT’S HOT IN TUCSON 2021” IN PRINT The virtual “What’s Hot in Tucson 2021” is an insert in Mineralogical Record magazine. You can also check with Bluecap Productions, as it will be available through them.

78 ROCK&GEM | WWW.ROCKNGEM.COM

Also, each dealer featured on the program has a copy of their presentation. Plus, at the end of this article, I’ll provide the code that will give you access to the virtual “What’s Hot in Tucson 2021.” For more than a year, the mineral hobby and business have suffered from the virus pandemic. If there is anything good that has come from this, it is the increased importance of virtual events like the Bluecap Production “What’s Hot in Tucson 2021,” which has explored the future of our hobby, which is changing even more rapidly since the pandemic. Changes in our hobby have been many and dramatic since I began collecting over 85 years ago. To borrow an old phrase, “You haven’t seen anything yet.” This 2021 “What’s Hot” series is just a harbinger of changes that will advance mineral education, disseminate information, foster special activities and programs, and grow our hobby as never before. One change that has already happened is the formation of an under age 40 group mentioned earlier. It started when several young collectors were chatting at the Tucson Show. This cluster of young collectors joined together to help each other, share information, exhibit their minerals, and be proactive in the hobby. The Young Mineral Collectors, as


On the Rocks

An aerial view of Mineral City Complex in Tucson, Arizona. MINERAL CITY COMPLEX

they call themselves, are sharp, come from all corners of the country, know good minerals, and are determined to become advanced collectors. Some of them already are!

DEALERS CHANGING LOCATIONS Another change on the horizon has to do with some of the top mineral dealers we enjoy seeing at the major Tucson events. One of the City of Tucson buildings that housed the Chamber of Commerce on the corner of St. Mary’s Blvd. and Main St. has been sold to mineral dealers. The plan is to house a group of major high-end mineral dealers in that building. This move will undoubtedly have a noticeable impact on other shows that currently house these dealers, as they may drop the established shows and concentrate on one location. Additionally, a useful tool on the internet that has grown in importance is Mindat. It offers up-to-date information about minerals in a crisp presentation that gives mineral information, references, and more. I use it regularly to check on something and to see what’s new. You should support Mindat financially, as many of us do. It offers up-to-date details as they come to light, which is something a book can’t do. The pandemic has certainly stirred greater use of the internet. One fellow, Ray Hull, started what is now a successful Facebook source for buying and selling minerals. Others are doing the same thing. And the internet is also where you can enjoy the once-a-week program “Mineral Talks Today.” Bluecap Productions and others can see and are working toward a future where you’ll be able to enjoy live broadcasts from mineral shows. Imagine a time when I will be co-hosting “What’s Hot” live from a major show, describing specific exhibits or new minerals, interviewing dealers, collectors, miners, or scientists on the event floor. Imagine being able to see Tucson or Munich shows as they are happening.

As is the case in a number of the shows sites in Tucson, each dealer shop in the Mineral City Complex has its own entrance so it can operate at any time the owners choose. BOB JONES

CHANGING THE SHOW TIME STRUCTURE The other thing happening is that mineral dealing in Tucson is no longer confined to promoted show dates. Dealers can now go outside the confines of a show and do business in an informal setting like the Mineral City Complex, with nearly 100 dealers showing their top specimens and open for business almost anytime. These dealers can warehouse their stock on site and still operate a formal business any day there are shows in Tucson. They can even open by appointment anytime during the year. You can bet your favorite mineral on it! These innovative efforts are just a taste of what we can expect in the future of our hobby. Mineral shows will still be with us, but the serious collector will be spending more time at less formal dealer gatherings like the Mineral City complex in Tucson. Decades ago, dealers who wanted to sell minerals had to join a show venue for the simple reason that they could not set up shop on their own; they had to become part of an organized event usually put on by a club, sharing costs and space for a nominal fee. Clubs made this possible for even a small dealer to set up and sell within the confines of an organized mineral show where expenses could be shared.

WWW.ROCKNGEM.COM | JULY 2021 79


On the Rocks

This unoccupied former Tucson Chamber of Commerce building will be the new home for high value mineral dealers. BOB JONES

We all know the cost of minerals has risen dramatically in the last several decades for many reasons. This fact is particularly true of the finest specimens that can now cost as much as a home. In the 1970s, I bought a choice specimen of copper for $4,200, which was a lot of money for a working teacher. That same specimen today has been judged to be worth several tens of thousands of dollars now. That’s crazy, but that is also reality! My point is that today’s more active full-time mineral dealers are making enough money that they no longer have to depend on club or promoted shows to make a living. They can afford to branch out on their own by using the internet or setting up shop where there is a major show. This is the function of the Mineral City Complex. Nearly 100 dealers operate their own mineral stores and can open when they please, all year long if they choose. This setup also functions as a workshop and for storage. The result of this is that dealers who have participated in the main show in Tucson for decades have the choice of dropping out and avoiding the high cost and restrictive controls in a cityowned building and becoming independent dealers. This is obviously a major change in the future of shows in Tucson. While the skeletal structure of the Tucson event was happening in Tucson in 2021, the growth of the Mineral City complex was continuing. This one location, already an important mineral center, has literally evolved as the center of mineral activities in Tucson. Located north of Tucson’s downtown a mile, at Lester Avenue and Oracle Road, it is the place for mineral collectors to be now. The idea of Mineral City was to concentrate many mineral dealers in one area for the convenience of collectors. When I was there in February, I was in three buildings where clusters of dealers were already set up, and work was progressing on several more buildings planned. Also in the planning are a large recreation/social area and available food when done. Many well-known U.S. and foreign mineral dealers who come to Tucson have a facility there already. They may still participate in the organized shows, but the Mineral

80 ROCK&GEM | WWW.ROCKNGEM.COM

City complex is there to stay. I may be wrong, but I can’t think of anywhere else in the world where you can visit 100 individual mineral shops in one area. When I visited China, the largest cluster of mineral shops I visited was about one city block long in Hunan Province. Not all the shops in Mineral City were open this year. Many European dealers simply could not come to the U.S., quarantine for two weeks, and remain for two more weeks. The cost alone would be prohibitive. According to reports, dealers who did open were fairly busy. Health controls required no more than four visitors in a shop at a time, but buying varied, with weekends the busier time. The few dealers I chatted with later were satisfied but looking forward to next year! As control over the virus strengthens, shows for the rest of this year are a light at the end of the tunnel. One advantage of being my age (I hit 95 this year) is that you get shots. Luckily, my body is too dumb to react to shots. Be that as it may, I’m headed for one of my favorite, the East Coast Show, in early August at Big Expo Fairgrounds, West Springfield, Mass. I have given three talks there every year for as long as the show has been in operation.

Here I am having the honor of chatting with my son Evan, co-owner of Unique Minerals, for “What’s Hot In Tucson 2021.” BLUECAP PRODUCTIONS

September on my calendar is set aside for the Denver shows. And it looks like there are some major changes happening for the 2021 September shows in Denver. The big show in the Coliseum is always worth a prolonged visit. The traditional Merchandise Mart show is canceled, and a new location for the Fine Mineral Show is to be in the downtown convention center. Be sure to check in on Bluecap’s virtual “What’s Hot in Tucson 2021” on the internet at: https://www.youtube.com/ channel/UCSIGYON34E_XN97bJAPqYuA. Bob Jones holds the Carnegie Mineralogical Award, is a member of the Rock hound Hall of Fame, and has been writing for Rock & Gem since its inception. He lectures about minerals, and has written several books and video scripts.


Marketplace

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Advertiser Index A & S Opals 81 Astro Gallery of Gems Inside Back Cover Blaine Reed 31 Blue Stone 77 Bonanza Mining Jade & Gold 77, 81 Cam’s Crystal Gallery 77 Condor Agate Mine 5 Covington Engineering Co. 7 Cynthia Wood 77 Excalibur Mineral Corporation 77 Gem Miners Jubilee 31 Gilman’s 63 Gray’s Rock & Gifts 77 Great Canadian Prospecting Co. 77 Harold Jeff Best 77 Jesco Products 49 John E. Garsow Gems & Minerals 69 Johnson Brothers Back Cover Joseph P. Stachura 49 Jox Rox 77 Kingsley North Inc. 3, 63 Lot O’ Tumbler 77, 81 Love of Rocks 81 Mineral Auctions 81 Minnesota Lapidary Supply 49, 69

Nature’s Treasures 69 Nevada Mineral & Book Company 39 New Era Gems 49 Opal Resources Canada Inc. 81 Pioneer Gem Corp 49 Poland Mining Camps 63 Prescott Gem & Mineral Club 8 R & T Rocks 77 Radical Rocks 77 Raytech Industries 81 Rock N Spheres 81 Ross Metals 49, 69 Royal Peacock Opal Mine 31 Samson Gems 63 SilverSmithingClass 69 Spanish Stirrup Rock Shop 5 Stone Goddess Designs 77 Sunstone Store 31 The Gem Shop Inc. 17 The Village Smithy Opals 7 Treasures of the Earth 69 Tru-Square Metal Products 8 Ultra Tec Inside Front Cover

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PARTING SHOT

ROCKS, MINERALS AND JEWELRY

Yellow Feather Jasper Cabochon The uncommon Yellow Feather jasper used to create this cabochon inspired the lapidary artist, Erin Dana Balzrette, to give it the name “Sundown Cabochon.” As Erin explained, the image that presents itself when looking at this stone is that of looking up through the branches as the evening color fills the sky. 43 x 41mm. LAPIDARY ARTIST: ERIN DANA BALZRETTE, TREE CLIMBERS STONES | PHOTO BY ERIN DANA BALZRETTE

82 ROCK&GEM | WWW.ROCKNGEM.COM


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