The World of Diamonds
Today diamonds are mined in about 25 countries, on every continent other than Europe and Antarctica. Though, only a few diamond deposits were known until the 20th century, when scientific understanding and technology extended diamond exploration and mining around the globe. For 1,000 years, starting in approximately the 4th century BCE, India was the only source of diamonds. In 1725, important sources were discovered in Brazil, and in the 1870s major finds in South Africa marked a dramatic raise in the diamond supply. Additional main producers now include several African countries, Siberian Russia, and Australia.
It is a modern misconception that the world's diamonds come mainly from South Africa: diamonds are a world-wide resource. The general characteristic of primary diamond deposits is the ancient terrain that hosts the kimberlite and lamproite pipes that bring diamonds to Earth's surface.
The map above shows both the main deposits and the ancient bedrock, both the 2,500-million-year-old archons and less productive 1,600 to 2,500-million-year-old protons, that contain the diamond pipes. The diamonds in minor deposits have been moved by erosion away from the pipes.
The massive increase in diamond production in the 20th century is shown on this graph. India's maximum production, perhaps 50,000 to 100,000 carats yearly in the 16th century, is very small by modern standards. Brazil and Venezuela are barely visible compared to South African production following discoveries in 1867. For the most part, except for major wars and economic recessions, diamond production has been progressively increasing since then, with non-African sources growing in relative proportion. Major production is now dominated by Australia, Botswana, Russia, and Congo Republic (Zaire), but South Africa is still a main producer, in both volume and value.
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