Siderite is a mineral composed of iron(II) carbonate (FeCO3). Its name comes from the Ancient Greek word σίδηρος (sídēros), meaning "iron". A valuable iron ore, it consists of 48% iron and lacks sulfur and phosphorus. Zinc, magnesium, and manganese commonly substitute for the iron, resulting in the siderite-smithsonite, siderite-magnesite, and siderite-rhodochrosite solid solution series.
Siderite
Siderite from Redruth, Cornwall, England.
Siderite crystals with galena and quartz. Size: 6.2 cm × 4.1 cm × 3.6 cm (2.4 in × 1.6 in × 1.4 in).
Disc-shaped, brown siderite crystals perched upon chalcopyrites.
Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the form of magnetite (Fe3O4, 72.4% Fe), hematite (Fe2O3, 69.9% Fe), goethite (FeO(OH), 62.9% Fe), limonite (FeO(OH)·n(H2O), 55% Fe), or siderite (FeCO3, 48.2% Fe).
Hematite, the main iron ore found in Brazilian mines
Stockpiles of iron ore pellets like this one are used in steel production.
An illustration of iron ore being unloaded at docks in Toledo, Ohio
Banded iron ock, estimated as being 2.1 billion years old