The ore must be a rock or mineral that contains valuable constituent, can be extracted or mined and sold for profit. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining is the extraction of valuable geological materials from the Earth and other astronomical objects. Mining of sulfur from a deposit at the edge of Ijen's crater lake For other uses, see Mining (disambiguation).
