Info on Chalcedony compiled by Wyn W. Purwinto, 2011. Chalcedony Facts, Information and Description Chalcedony and its named varieties are well represented in various birthstone charts and can be found for all the months except January, April, and November. It is also listed as a birthstone for all the Zodiac signs except Taurus, Cancer, Scorpio and Sagittarius. The term chalcedony is derived from the name of the ancient Greek town Chalkedon in Asia Minor. Chalcedony, which is found worldwide, is the name for a group of stones made of a microcrystalline or cryptocrystalline variety of quartz, which means the quartz crystals are too small to be seen without high magnification. In jewelry usage, the name Chalcedony is usually applied only to the light blue translucent and waxy form. Other stones in this group are know as agate, jasper, petrified wood, bloodstone,petrified dinosaur bone, fire agate, tiger's eye, chrysocolla,chrysoprase, onyx, sardonyx, and carnelian. Chalcedony is found in almost every color including: white, gray, black, brown, brownish red, orange, yellow, light to dark green, blue, lavender or, in the case of agates and jaspers, combinations of those colors. Folklore, Legend, and Healing Properties: Native American Indians believed chalcedony was a sacred stone and used in the spiritual ceremonies of the tribe. It is thought to increase vitality, stamina, and endurance and to promote emotional balance and charity while relieving melancholy, fever, gallstones, and eye problems.
Source: http://www.bernardine.com/gemstones/chalcedony.htm
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Blue Chalcedony Chrysoprase Blue Chalcedony Blue Chalcedony Lavender Chalcedony Blue Chalcedony Chrysoprase Carnelian Moss Agate Plume Agate Blue Lace Agate Fire Agate Picture Jasper
14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
Red Jasper Willow Creek Jasper Biggs Jasper Onyx Sardonyx Bloodstone Chrysocolla Tiger's Eye Chrysocolla Petrified Palm Wood Petrified Dinosaur Bone Petrified Dinosaur Bone
Info on Chalcedony compiled by Wyn W. Purwinto, 2011. Chalcedony /kælˈsɛdəni/ is a cryptocrystalline form of silica, composed of very fine intergrowths of the [2] minerals quartz and moganite. These are both silica minerals, but they differ in that quartz has a trigonal crystal structure, while moganite is monoclinic. Chalcedony's standard chemical structure (based on the chemical structure of quartz) is SiO2 (silicon dioxide). Chalcedony has a waxy luster, and may be semitransparent or translucent. It can assume a wide range of colors, but those most commonly seen are white to gray, grayish-blue or a shade of brown ranging from pale to nearly black. The name chalcedony comes from the Latin chalcedonius (alternatively spelled calchedonius). The name [3] appears in Pliny the Elder's Naturalis Historia as a term for a translucid kind of Jaspis. The name is [4] probably derived from the town Chalcedon in Asia Minor. Source: https://en.wikipedia.org/wiki/Chalcedony ----------------------------------------------------------------------------------------------------------------------------- --------------Chalcedony is not scientifically its own mineral species, but rather a form of Quartz inmicrocrystalline form. However, the name is an old name, and almost all mineral reference guides and collectors distinguish Chalcedony separately from Quartz. In the gem trade, the name Chalcedony usually describes only white or blue Chalcedony, to distinguish it from the multicolored banded variety Agate and other unique varieties of this mineral. Chalcedony is quite varied in its formation habits. It sometimes occurs in geodes, lining the cavity with mammilary blobs. Its Agate variety is also found in geodes, commonly lining the outer layer underneath the larger Quartz crystals. Chalcedony also forms pseudomorphs after organic material. A well-known example is petrified wood, in which the wood has been completely transformed into Chalcedony. In the Petrified Forest National Monument in Arizona, an entire forest was transformed into petrified wood. Remains of this ancient forest can be seen in the hugesilicafied logs that are found in the area. Another well-known pseudomorph is Chalcedony after coral. In the Tampa Bay in Florida, coral has been chemically replaced by Chalcedony, and its original form is preserved. Another famous Chalcedony pseudomorph is Tiger's Eye. This popular variety has very unique optical properties in the form of a bronze sheen that is caused by the fibrous mineral Crocidolite that was chemicallyreplaced into Chalcedony through pseudomorphism. Impurities are frequently present in Chalcedony. They may form a moss like growth in the mineral, forming what is known as Moss Agate. Another example is Dendritic Agate, a variety of Chalcedony containing manganese oxide impurities that form fabrications resembling trees. These forms of Agate are not true Agates, since they lack the banding. Source: http://www.minerals.net/mineral/chalcedony.aspx