Sri Lanka is a rich source of quartz. Vein quartz deposits of over 99.98% purity are found in the central highlands of the island. Vein quartz normally occurs on the surface as very large boulders and in some instances can cover areas of over 4 hectares. Deposits have even been known to extend inwards in depth. Although no estimates of deposits are currently available, the deposit mined by Alchemy Boulders has been estimated to contain 20 million tons of quartz.