Siderite - Natural minerals and crystals

Siderite is a mineral composed mainly of iron, carbon and oxygen, which forms well-formed crystals in prisms. Its color varies from dark gray to brown, and its luster is dull. Siderite generally forms under conditions of low temperature and pressure, associated with the presence of sulphides and bicarbonates in metalliferous waters. This type of formation is sometimes seen around iron ore veins, and so siderite will often serve as a marker identifying the presence of iron ore. Siderite is often used as an iron ore. The largest reserves are in Europe, North America and South America. It is also used to produce cements and ceramics, and for livestock feed.