Hematite

Hematite, also spelled as haematite, is the mineral form of iron(III) oxide (Fe₂O₃), one of several iron oxides. Hematite crystallizes in the rhombohedral lattice system, and it has the same crystal structure as ilmenite and corundum. Hematite and ilmenite form a complete solid solution at temperatures above 950 °C (1,740 °F).