Ore is found in specific types of rocks and geological settings where metals have been naturally concentrated enough to be mined profitably.

What ore is

  • Ore is a natural rock or sediment that contains enough valuable minerals (often metals) that it can be mined and processed at a profit.
  • Originally the word “ore” referred mostly to metallic minerals, but today it can include some nonmetallic materials as well.

Where ore is generally found

  • Metallic ores are commonly found in igneous and metamorphic rocks, where processes like magma cooling and high-pressure alteration help concentrate metals.
  • Many ores also occur in certain sedimentary rocks and soils, where metals have been moved and deposited by water, wind, or chemical reactions.

Common geological settings

  • Igneous settings: Cooling magma deep underground or lava at the surface can form ores of copper, tin, diamonds, silver, and mercury.
  • Hydrothermal veins: Hot, metal-rich fluids move through cracks in rocks and precipitate ores like gold, silver, and copper in veins.

Other important deposit types

  • Placer deposits: Heavy minerals such as gold, tin, and platinum accumulate in river beds, beaches, or other places where flowing water slows down.
  • Massive sulfide and sediment-hosted deposits: Large bodies of copper, lead, zinc, and other metals can form on ancient seafloors or within sedimentary basins.

Where in the world ore is found

  • Major iron ore reserves occur in countries such as Australia, Brazil, China, India, Russia, and Ukraine.
  • Large copper ore deposits are found in Chile, Peru, China, the Democratic Republic of the Congo, and the United States, which together produce a big share of the world’s copper.