Stephanite
Formula: Ag5SbS4
Species: Sulfosalts
Colour: Lead gray or black
Lustre: Metallic
Hardness: 2 – 2½
Specific Gravity: 6.26
Crystal System: Orthorhombic
Name: Named after the Austrian Mining Director/engineer and life-long mineral collector, Archduke Stephan Franz Victor von Habsburg-Lothringen (1817-1867).
Type Locality: Freiberg, Mittelsachsen, Saxony – Germany
A less common Ag-rich silver sulphosalt.