Siderite

Siderite is an iron carbonate mineral with the formula FeCO₃. It commonly forms in sedimentary environments and has been mined as an iron ore.

Carbonate minerals: Minerals built around the carbonate ion, CO₃²⁻, often combined with metal cations. Siderite belongs to this mineral family, whose crystal structures and reactions help explain its properties.
Diagenesis: The physical, chemical, and biological changes sediments undergo after deposition and before metamorphism. Siderite commonly precipitates during sediment burial and alteration.
Iron ore: Rock or mineral material from which metallic iron can be extracted economically. Siderite has served as a source of iron, though its carbonate content can complicate processing.
Ankerite: A calcium-iron-magnesium carbonate mineral in the dolomite group. It resembles siderite chemically and may occur with it in iron-rich sedimentary deposits.
Iron: A chemical element with symbol Fe and atomic number 26, abundant in Earth’s crust and core. Iron occupies the metal site in siderite’s chemical formula.
Iron reduction: The chemical process in which iron gains electrons, commonly converting ferric iron to ferrous iron. Reduced iron is more soluble in anoxic waters and can combine with carbonate to precipitate siderite.
Ironmaking: The industrial production of metallic iron from iron-bearing materials. Siderite ore must be roasted or otherwise processed before iron can be efficiently smelted.
Rhodochrosite: A manganese carbonate mineral with formula MnCO₃. It shares siderite’s carbonate structure type while manganese replaces iron.
Carbonate ion: A polyatomic ion with formula CO₃²⁻, composed of one carbon atom bonded to three oxygen atoms. This ion combines with iron to form siderite’s carbonate composition.
Anoxic environment: An environment with little or no dissolved oxygen. Oxygen-poor sediment helps preserve dissolved ferrous iron needed for siderite formation.

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