Creation of DiamondsImpact on Society 
Mining
The deposits that diamonds are mined from are differentiated as primary and secondary (as well as tertiary, though these are much less common). Primary deposits are the actual underground volcanic remains, known as kimberlite pipes. Kimberlite is a name for the diamond bearing rock, and it contains on average 0.5 carats of diamonds (both gem and industry grade) per 1 ton of material. Other diamond bearing rocks exist, such as lamproite, which is the source of the Australian diamonds. Some mines have a higher yield — the Australian Argyle mine is the world's leader in diamond production with 6.6 carats of diamonds per ton of lamproite and yearly output of about 40 million carats. Compare this number with 12 million carats produced by India since ancient times and 16 million provided by Brazil in 18th and 19th centuries. At the same time some mines are only capable of getting 0.05 carats per ton of excavated material.
Mining the primary deposits consists of excavating large open pits or extensive underground tunnels to get the kimberlite out of the ground and into processing facility. It is a feast of engineering to do this safely and efficiently. Most mines in the beginning of the industry development in Africa were open pits. There is a pit near the city of Kimberly in South Africa, aptly named the Big Hole, which is 1000 meters deep. It was built in 1903 by hands, since no modern excavating equipment existed then.
Amount and quality of kimberlite is not consistent at different depth. Different layers of kimberlite are distinguished by colour and get their names from it. The first layer, closest to the surface, is called yellow ground, it is yellow because of heavy erosion by wind and water and is generally easier to mine. The second layer is blue and less eroded, and the last layer is grey and is located below 500 meters underground. Generally the efficiency of mining decreases with depth, since the lightweight rocks get weathered out from kimberlite close to the surface, leaving diamonds behind.
The secondary deposits are simply deposits of diamonds that were washed out from the primary deposits by water, and were left on the river banks or sea shores. These were mined since the ancient times, the same way gold and other minerals were often mined from rivers. Such deposits are usually called alluvial.
The efficiency of the primary deposits is usually lower than of secondary, mostly because there is much more worthless rock in kimberlite; it is washed away from the alluvial deposits and leaves all the diamonds. Also, the diamonds from alluvial deposits are generally of higher quality, since only well formed crystalls will survive the stressful trip to the secondary deposits. On the other hand, because of the stress of this trip, large crystals are more likely to be found in the primary deposits, before they had a chance to break apart.
After the initial material has been mined, it is transported to a special facility where the rock is crushed to reveal the diamonds. Today, x-rays are used to determine if there are diamonds in the rock, and the rock can then be crashed in such a way as to preserve larger stones from damage. This is possible because all diamonds fluoresce when subjected to x-rays. Before this technique was invented kimberlite was crushed into pieces of about 3 cm in size for easier processing, even if that meant larger stones would be destroyed.
One great example of a stone that survived such technique was the Cullinan diamond, found in 1905 in the Premier mine in the South Africa (this mine produced a lot of the world's largest and most famous diamonds). It was the largest rough diamond, sized over 3100 carats (over 620 grams). The size and quality of the diamond are amazing and remain unmatched after over 100 years of extensive mining. It has been cut into 9 large pieces and 96 smaller brilliant cut diamonds, all of which belong to the British crown and are on display with other crown jewels. The image above left shows the rough Cullinan diamond presented by the mine's employee, as well as the largest cut diamond it produced, incorporated into the Royal Sceptre.
Currently, about 60% by value of all rough diamonds are mined in Africa, about 35% in Australia, and the remaining 5% in other regions such as Canada, Russia and Brazil. Aside from commercial contracts and agreements that exist between the members of the diamond trade, the worldwide distribution of rough diamonds is controlled by an international body known as the World Diamond Council (WDC). The WDC oversees mining and trade of rough diamonds to ensure their safety and legitimacy in each country involved in the diamond industry.
Creation of DiamondsImpact on Society
