Diamonds rarely appear in sufficient quantity to make mining practical or affordable. Until 1725, diamonds were mined almost solely in India.
They were then discovered in enough quantity to be mined in Brazil. The largest deposits of diamonds have been found near Kimberley, South Africa. Most of the diamonds in the world are now mined in Africa, though half of them are used for industrial purposes rather than as jewels.
Diamonds are found in small amounts in many other places worldwide. In the United States, diamonds have been found on the beaches of northern California, in the Appalachian Mountains, and in glacial deposits in Ohio, Michigan, and Wisconsin.
The only actual diamond mine in the United States was in Arkansas. It yielded some 40,000 diamonds and is now a tourist attraction.