Iron ore is a mineral substance which, when heated in the presence of a reductant, will yield metallic iron (Fe). The iron ore, usually, very rich in iron oxides (Fe3O4 and Fe2O3). Iron ores are mostly dark grey to rusty red in color and high specific gravity. Two main types of iron ore used for iron making – Magnetite (Fe3O4) and Hematite (Fe2O3).