Siderite
Image: Raimond Spekking (CC BY-SA 4.0)
Mineral NameSiderite
Chemical FormulaFeCO₃
Mohs Hardness3.5
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavageperfect rhombohedral {1011}
Fractureuneven
Specific Gravity3.96
Colorsyellowish-brown, brown, reddish-brown, gray, green, white, colorless
Transparencytransparent
Type LocalityFriedrich Wilhelm mine, Herdorf, Siegerland, Westphalia, Germany
Mineral GroupCarbonates
Usesminor ore of iron, flux in steel production, collector
Associated Mineralschalcopyrite, quartz
Raritycommon
Description
Siderite typically forms rhombohedral crystals, often with curved faces, or can be massive, granular, or botryoidal. Its color ranges from yellowish-brown to dark brown, sometimes gray or greenish.
Geological Context
Siderite forms in sedimentary environments, often in concretions, or as a gangue mineral in hydrothermal veins. It is also found in metamorphic rocks and is common in iron ore deposits.
