Diamonds have been found all over the world, the most ancient and famous being the old Indian deposits that were worked from earliest times. Till about the late 1700s, all the iamonds in the world were found in fields and on river beds, mostly near Hyderabed in the Deccan Plateau. Large stones like the Kohinoor were found there around 1300 AD. The town of Golconda so became the centre of the diamond trade of the world. In spite of the output from India, Borneo and, to some extent Brazil, diamonds were very rare. Valuable diamond fields in the gold-mining area of Minas Gerais were discovered in Brazil about 1725. Portuguese merchants took Brazilian diamonds to Goa, India, to pass them off as Indian stones. Mining was carried out to intensively in Brazil that the main ares wee almost exhausted within twenty years.
At about the time that the Brazilian fields were being depleted, the first diamond field of South Africa was discovered in 1866 AD, when children of a Boer farmer found 'a pretty pebble' in the sandy bed of the Vaal River. Four years later, diamonds were found in the earth far from a river source, and the practice of dry-digging for diamonds was born. More sophisticated mining techniques allowed deeper subterranean digging, as well as more efficient river marine mining than ever before. By 1871, world annual production, mostly from South Africa, exceeded a million carats. Soon South Africa had the monopoly for diamond production, until major deposits were found in Siberian permafrost in 1954. Currently Western Canada is the site of the world's newest diamond rush. Diamonds have also been found in the Urals and in Australia and these sources compete with South Africa.