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www.mineralgallery.co.za Minerals A-E |
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Diamond |
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Name
Diamond
Chemistry
C, Carbon
Uses
Gemstone and as an abrasive in cutting wheels.
Color
Yellows, light blues, white, colorless, black, greenish and even reddish.
Hardness
10
Specific gravity
3.5
Streak
White
Crystals
Isometric forms such as cubes and octahedrons.
Accompanied by:
Often found in a conglomerate like kimberlite
Similar to:
Cubic zirconia when facetted
Diamonds melt at 3820 degrees centigrade and is formed under enormous pressure and heat.
It is four times harder than the nearest stone to it, which is the corundum. The diamond and graphite shares the same chemical formula, C. They are polymorphs of one another.
The diamond has always been regarded as the King of the gemstones. It has a very high luster and the supply has been controlled by a consortium called De Beers. This has led to the diamond retaining it's high prices over the years. Diamond is the ultimate abrasive and is used to cut and drill a variety of material.
The history of diamonds in South Africa.
Way back in 1867 a young boy picked up a shiny stone in the vicinity of Hopetown close to the Orangeriver. A neighbour saw the stone and took it over from Daniel Jacobs. He then gave it to a dealer with the name of John O'Reilly who sold it to the Governor of the Cape for a sum of $ 150. This diamond weighed 21.75 carat.
This led to several prospecting trips by Dr Atherstone and others for the source of the diamonds. It took two years for the second big stone to be found. This one weighed 82.5 carat and was named the star of South Africa. This diamond was bought for 500 sheep, a horse and 10 bulls from a local Griekwa. It was then sold for a huge sum of $ 6500.00 also to the Governor. This gave rise to the first diamond rush. Everybody rushed of to the interior to go and find their fortune. In 1870 almost 50 000 people joined this diamond rush. They looked for diamonds next to the riverbeds.
But in the autumn of 1870 a boer with the name of De Klerk discovered a diamond of 50 carat in a rock that was later to be named kimberlite after Lord Kimberley. So everybody started looking for the garnet, ilmenite and chromediopside soil that makes up the kimberlite. This led to the discovery of several kimberlite pipes of which the most famous one was at the town of Kimberley.
At first the diamonds were mined by individuals with small claims of 9.1 x 9.1 meter. They were working at different tempos and this resulted in undercuting and claims collapsing and people getting injured. Rhodes and Barnaby saw the problems and through their amalgamation the company De Beers came about. This gave rise to an industry that were able through their clever marketing to keep the diamomd market stable worldwide.
Diamonds were then discovered in the Namib and this gave rise to the Spergebied in Namibia. A huge area is inacsessable to all,because of the fact that diamonds have been found there. Stories of smuggling from this area abound.
Aluvial diamonds have also been found near Lichtenburg and Ventersdorp and in 1927 as many as 140 000 people were working the claims there and over R 9.9 million Rands worth of diamonds were retreived that year. Oversupply and the depression of 1932-1933 stiffled this mining operation.
