Hematite

A piece of hematite

Hematite or haematite is the main ore of iron. It is mostly iron(III) oxide. Millions of tons are dug up every year. This is usually to feed to blast furnaces to make steel. It is a mineral related to corundum. It is an oxide.

It has a metallic luster. It has no cleavage (the way a mineral breaks). It has a fracture. The fracture is irregular and uneven. Hematite on the hardness scale is 5 to 6. It has a bright red to dark red streak. To find the streak, you take the mineral and run it across a plate of unglazed porcelain. The colours can be metallic grey to a dark, rough and earthy red colour. Hematite has the chemical formula of Fe₂O₃.