Hematite is a common iron oxide compound and occurs naturally in black to steel or silver-gray, brown to reddish-brown, or red colors. It is mined as an important ore mineral of iron and is electrically conductive.

Hematite varieties include kidney ore, martite (pseudomorphs after magnetite), iron rose and specularite (specular hematite). While these forms vary, they all have a rust-red streak. Hematite is not only harder than pure iron, but also much more brittle.

Use of the red chalk of this iron-oxide mineral in writing, drawing, and decoration is among the earliest in human history. To date, the earliest known human use of the powdery mineral is 164,000 years ago by the inhabitants of the Pinnacle Point caves in what now is South Africa, possibly for social purposes.[10] Hematite residues are also found in graves from 80,000 years ago.