Tetrahedrite
ID: 34
Tetrahedrite
Chemical Formula
(Cu,Fe)₁₂Sb₄S₁₃
Hardness (Mohs)
3 - 4.5
Crystal System
Isometric
Streak
Black to brownish-black
Luster
Metallic
Diaphaneity
Opaque
Color
Steel-gray to iron-black
Crystal Habit / Mode of Occurrence
Isometric - Hextetrahedral; commonly tetrahedral crystals (often with modified faces), often twinned; also massive, granular.
Fun Facts
Tetrahedrite was historically a significant source of silver, as silver can substitute for copper in its structure, sometimes making it a "silver ore" rather than just a copper ore. Common Uses: Ore of copper and antimony; often an important ore of silver.