Bauxite, an aluminum ore, is the world's main source of aluminum. It consists mostly of the minerals gibbsite Al(OH)3, boehmite γ-AlO(OH) and diaspora α-AlO(OH), mixed with the two iron oxides goethite and haematite, the clay mineral kaolinite and small amounts of anatase TiO2, Ilmenite, FeTiO3, and FeO TiO2.