Alluvial Mining is the process of extracting diamonds and other precious stones from the sand and mud found along river banks. The diamonds and precious stones have been carried by a river’s force from their source in a Kimberlite rock formation and deposited along the river’s banks. Small scale miners sift through the sediment deposits to find the precious stones using shovels, bare hands, or sieves. Larger operations of alluvial mining separate the earth from the body of water in order to simplify the mining process. The concentration of diamonds is then separated into several size ranges, each placed onto a table, where each diamond is inspected by eye.
Approximately 10% of the world’s diamonds are mined through industrial alluvial mining, and 14% through small scale, informal alluvial mining. Alluvial mining takes place in North America, in South America, and in Africa.