Description
Hematite (from Greek: αιμία, haima, blood) is a mineral composed primarily of ferric oxide crystals (iron(III) oxide, Fe2O3), one of the iron oxides. It occurs alongside other varieties such as red bloodstone and grayish-black to black iron luster and micaceous iron. The mineral has a hardness of between 5 and 6. The so-called streak, or streak color, the color the mineral imparts when rubbed over an unglazed porcelain dish, is usually a characteristic blood red—from which the mineral derives its name. The mineral may contain traces of magnesium, manganese, and titanium. Hematite occurs both as a gangue mineral and in sedimentary layers. It is often the cause of the red coloration of many rocks. Other iron ores such as magnetite, limonite, and iron spar often occur alongside hematite. When magnetite has been converted to hematite, it is called martite. The mineral occurs worldwide, in Europe in Germany, among other places, in the Lahn region, where the world's largest concentration of iron ore is located.
