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INSIDE AFRICA’S FIRST MINE WITH AN ALL-FEMALE WORKFORCE
he discovered 50 stones in the river gravels on a farm near Lichtenburg. This led to the famous Lichtenburg diamond rushes of 1926/27.
In order to be fair to the thousands of diggers who wanted to peg claims on the newly discovered deposits, government officials organised races where diggers could - at the firing of a gun - start to run towards the area where they believed their fortune lay. Tens of thousands of pegs were planted by youngsters and the elderly (some on crutches) and middle- distance runners who were employed by diggers.
In a few years, Lichtenburg produced more than £10 million worth of diamonds that were dumped on the already weak diamond market, causing its near-collapse in the late 1920s. A number of diggers are still active today, but their production is only a fraction of the erstwhile fortunes which these river gravels produced.
As many as 25 000 people took part in a single rush in 1926 in the Lichtenburg district.
BOTSWANA – A COUNTRY BUILT ON SMALL STONES
In 1966, Botswana was one of the 25 poorest nations in the world. Then its destiny changed. Diamonds were discovered at Orapa, derived from "bovapa", meaning “resting place of lions”, and the country never looked back. Subsequent discoveries were made at Jwaneng (aptly named “place of small stones”) and at Letlhakane.
De Beers started to look for diamonds in Botswana in 1955 but only discovered the pipe at Orapa in 1967. The Orapa pipe is the second-largest kimberlite pipe in the world – with a surface area of 113 ha, the size of 152 soccer fields. The Big Hole at Kimberley only covers 4,8 ha.
At Jwaneng, the diamonds were hidden under 35-50 m of Kalahari sand. They might never have been revealed but for the termites that lived in the desert aeons ago when there was sufficient rainfall to sustain them. They burrowed deep into the earth in search of moist clay with which to build their mounds. When rains washed these mounds away, grains of indicator minerals associated with diamonds - such as garnets and ilmenites - were left behind. Geologists picked up these vital clues which led to the discovery of the buried pipes.
The cost of exploration and finding a viable kimberlite pipe is enormous. At Jwaneng, 249 large boreholes were dug to a depth of 200 m, as well as six shafts to a depth of 158 m. Geologists flew low over the desert in small aircraft, trailing sensitive instruments that could pick up magnetic anomalies over the hidden kimberlite pipes.
The Botswana mines are all 24-hours-a-day/six-days-a-week, open-pit operations. It is fascinating to see how the largest computerised hydraulic shovels in the world - the Demag 4855 - load 55 tons with every scoop and feed a fleet of 117-ton trucks, which haul the ore to the primary crusher and waste dumps.
Today, Botswana is the world’s largest producer of gem- quality diamonds (approximately 16 million carats annually). Diamond exports account for more than 60% of government revenues, over 70% of its foreign exchange and 40% of its GDP. Its bonanza has not been squandered, but has been used prudently to benefit every citizen in the land.
Ants carrying rough diamond crystals.
The Botswana government and its partner, De Beers, have been a shining example to the rest of Africa of how to exploit and benefit from the riches of which their continent has plenty.
Sorting rough production into categories.
Peridot: the evening emerald
Peridot is not only the birthstone for August, but the traditional stone for 16th wedding anniversaries. It symbolises clear thinking, wholeheartedness and light. In ancient times, it was believed that peridots’ bright sparkle could ward off evil during the night.
PERIDOT IS BOTH A DAY AND a night stone, maintaining its electrifying colour under artificial light and candlelight alike. For this reason, it is sometimes called the “evening emerald”.
The name “peridot” originates from the Arabic word “faridat”, meaning “gem”. Most peridots were formed deep inside the earth and delivered to the surface by volcanoes. Some also came to earth in meteorites, but these are extremely rare and unlikely to be found in retail jewellery stores.
Peridots’ origin stretches back to ancient Egypt, on the volcanic island of Zebargad in the Red Sea. The stones were so treasured by the Egyptians that they kept the island’s location a secret. With the fall of the Egyptian empire, the island fell into obscurity and was only rediscovered in 1906.
Today, large quantities of peridot are mined in the San Carlos reservation in Arizona, USA (though stones from America are generally much smaller and lighter than varieties from other locales). Peridot is also extensively mined in Pakistan and Kenya.
Peridot is a type of silicate mineral called olivine. It is one of the few gems that occur in only one colour (in this case, green). Its pigmentation is due to the presence of iron trace elements. Depending on the amount of iron present, peridots may appear lighter or darker, ranging from pale golden-green to intense olive green. The stone has what is called “high double refraction” – if one peers closely at it, one will see a clear double image of its pavilion facets. It rates 6,5-7 on the Mohs scale of mineral hardness and is best suited for jewellery that will not be bumped frequently, as it can scratch or chip easily. It can also be damaged by certain acids and even by long-term exposure to acidic perspiration.
Cleaning peridot is a delicate process. Never use a steam or ultrasonic cleaner, as it is vulnerable to thermal shock. It is safest to use a soft-bristled brush with a mild dish soap in warm water. Peridot should be stored with care to avoid being scratched by gems with greater hardness.
While synthetic peridots may have no general commercial availability or economically viable jewellery use, many simulated stones can be found on the market. Synthetic corundum and spinel gems, as well as cubic zirconias, are sometimes passed off as peridots. Perhaps the most frequently encountered peridot simulant is green glass. Although visually very similar, the physical and optical properties of these simulants differ significantly from those of the genuine article.
Peridots are relatively inexpensive. They can be set into many kinds of jewellery, casual or glamorous, without breaking the bank. And when clarity and carat permits are combined with excellent jewellery designs, the stones can fetch a decent price.
On the whole, they are just as attractive and desirable as any other gemstones, with many fascinating hidden stories waiting to be told.
