Hematite, HEHM uh tyt, is a mineral that supplies most of the world's iron. Hematite is a ferric oxide (a compound of iron and oxygen). In its purest form, hematite consists of about 70 percent iron. The mineral occurs in a variety of forms, including shiny crystals; grainy rock; and loose, earthy material. Hematite is black, steel-gray, brownish-red, or dark red, but a fresh scratch on hematite rock is blood-red. The word hematite means bloodlike. Red ocher, an earthy form of hematite, is used to color paint.