Iron ores are minerals from which metallic iron can be extracted. The iron itself is usually found in the form of magnetite (Fe3O4) or hematite (Fe2O3), both of which are iron oxides. However, as much of the pure magnetite and hematite ore has already been mined, modern iron mines rely on aggregate minerals such as taconite, which must be processed to remove non-iron-bearing components prior to smelting. Iron mines therefore produce tremendous amounts of waste causing environmental problems in the areas they are mined.
Iron ore is common worldwide, but commercial mining operations are dominated by seven countries: Australia, Brazil, the People's Republic of China, India, Russia, the USA, and Ukraine. World production averages one billion metric tons of raw ore annually.
Most iron ore is used in the production of steel.