A mineral form of iron (III) oxide, Fe₂O₃. It is the most important ore of iron and usually occurs in two main forms as a massive red kidney-shaped ore (kidney ore) and as grey to black metallic crystals known as specular iron ore.

Haematite is the major red coloring agent in rocks; the largest deposits are of sedimentary origin.

In industry haematite is used as a polishing agent (jeweler’s rouge) and in paints.