Localities and Formation of Diamonds
Diamonds are found in various parts of the world. In past centuries fine diamonds came from India. This is the world’s oldest major source of diamonds and has supplied stones for centuries to all parts of the globe. Indian diamonds are found in riverbeds. These stones were weathered out of source rocks and concentrated in streams over a period of many years. Such river deposits are termed alluvial, and Indian alluvial deposits were worked as early as 80 B.C. Much of our information about old Indian workings comes from the writings of the great traveler Tavernier, who lived and traveled in the 17th Century. Most of the Indian diamonds came from an area known as Golconda. Other Indian be-posits include those of the Brahmani River, the Panna diamond fields, and the mines of Sumelpur.
In the early part of the 18th Century, diamonds were discovered in Brazil, in an area later called Diamantina. They were not easy to sell because it was feared that a flood of Brazilian stones would depress diamond prices. To avoid the stigma placed on Brazilian diamonds, dealers sent them to India, where they were marketed as Indian gems. Later diamonds, like the Indian gems, are found as alluvium in riverbeds and stream deposits.
Diamonds were formed millions of years ago and can be mined today in locations that have once experienced volcanic activity. The following countries produce industrial-grade diamonds: Australia, Botswana, Brazil, China, Congo, Russia, and South Africa. Geologically speaking, natural diamonds are found in two environments. Most are found in kimberlites, which are pipe-like formations created as a result of volcanic and tectonic activity.
Diamonds are found in Venezuela (alluvial), Guyana, Borneo> and Australia. A diamond mine at Murfreesboro, Arkansas has yielded many small stones, as well as a few larger ones. The Uncle Sam Diamond. Weighing 40.23 carats in the rough, wan the largest diamond ever discovered in North America. Lt yielded a 12.42-carat emerald cut gem now in a private collection. The Murfreesboro deposit has been worked for years by visitors who would pay a small fee for the privilege of indulging in “diamond-hunting fever.” Small diamonds are still occasionally found.
Some diamonds have been found in Canada, in glacial deposits. These deposits were accumulated by glacial action that scoured vast portions of the country, and the source rocks have never been discovered. The U.S.S.R. is currently a leading producer of diamonds, the face. The world’s largest outside Africa. Mining conditions are very difficult due to the extreme cold.
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The vast majority of the world’s gem diamond comes from Africa. The first diamond discovered in Africa was found by a child in 1867. Within a few years a “diamond rush” had started in South Africa the helped to develop this rich and beautiful country.