Iron is one of the most abundant rock-forming elements, constituting about 5% of the Earth’s crust. It is the fourth most abundant element after oxygen, silicon and aluminium and, after aluminium, the most abundant and widely distributed metal. Iron ores are rocks from which metallic iron can be economically extracted.
Iron ore rocks are usually found in the form of hematite (Fe2O3) or magnetite (Fe3O4). About 98% of world iron ore production is used to make iron in the form of steel. Although iron in cast form has many specific uses (e.g. pipes, fittings, engine blocks), its main use is to make steel.
