Stephanite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 3.0)
Mineral NameStephanite
Chemical FormulaAg₅SbS₄
Mohs Hardness2
Crystal Systemorthorhombic
Lustermetallic
Streak Colorblack
Cleavagedistinct on {010}
Fractureconchoidal
Specific Gravity6.2
Colorsiron-black, lead-gray, steel-gray
Transparencyopaque
Type LocalityGrube Gnade Gottes, St Andreasberg, Revier St Andreasberg, Harz, Lower Saxony, Germany
Mineral GroupSulfosalts
Usesminor ore of silver, collector
Associated Mineralsargentite, native silver, galena, sphalerite, pyrite, calcite, quartz
Rarityuncommon
Description
The image shows dark, metallic-lustered Stephanite crystals, appearing as small, platy to tabular forms, some with bright reflections, embedded within a lighter, possibly quartz or carbonate, matrix. The overall color is dark gray to black, with some areas showing a duller, tarnished appearance.
Geological Context
Stephanite is a sulfosalt mineral that forms in low-temperature hydrothermal veins, often associated with other silver-bearing minerals. It typically crystallizes during the later stages of ore deposition in epithermal to mesothermal environments.
