Not every metal-bearing rock is worth mining. An ore is a natural concentration of one or more minerals from which a metal or other valuable commodity can be extracted at a profit. Economic factors as well as grade determine whether a deposit qualifies as ore.

Ores form through magmatic segregation, hydrothermal circulation, sedimentary processes, or weathering. Common ore minerals include oxides, sulfides, and native metals. The surrounding waste rock is called gangue. Beneficiation separates the valuable minerals from the gangue before metallurgical extraction.

Ore deposits are finite and unevenly distributed, making their discovery and responsible extraction matters of economic and strategic importance. Grades have generally declined as the richest deposits are depleted, requiring larger volumes of rock to be processed. Environmental management of mining and processing residues is an integral part of modern operations.

• Rock or mineral concentration economic to mine
• Contains extractable metals or commodities
• Formed by diverse geologic processes
• Defined by both geology and economics