Siderite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameSiderite
Chemical FormulaFeCO₃
Mohs Hardness3.5
Crystal Systemtrigonal
Streak ColorWhite to yellowish-brown
CleavagePerfect rhombohedral {1011}
FractureConchoidal to uneven
Specific Gravity3.96
Colorsyellowish-brown, brown, gray
TransparencyTranslucent
Type LocalityRedruth - St Day District, Cornwall, England, UK
Mineral GroupCarbonates
Usesminor iron ore, collector's specimens
Associated Mineralsquartz, chalcopyrite
Rarityuncommon
Description
This specimen showcases numerous yellowish-brown, bladed siderite crystals forming distinctive rosette-like aggregates, intergrown with clear to milky quartz crystals and minor metallic chalcopyrite on a rocky matrix.
Geological Context
Siderite commonly forms in hydrothermal veins, often associated with metallic sulfide ores like chalcopyrite and gangue minerals such as quartz, characteristic of the historic tin and copper mining districts of Cornwall.
