Tetradymite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 3.0)
Mineral NameTetradymite
Chemical FormulaBi₂Te₂S
Mohs Hardness1.5
Crystal Systemtrigonal
Lustermetallic
Streak Colorgray
Cleavageperfect on {0001}
Fractureuneven
Specific Gravity7.2
Colorssteel-gray, tin-white, silvery-white
Transparencyopaque
Type LocalityGlacier Gulch, Smithers, Omenica Mining Division, British Columbia, Canada
Mineral GroupSulfides
Usescollector, minor ore of bismuth, minor ore of tellurium
Associated Mineralsgold, quartz, pyrite, other tellurides, bismuth minerals
Rarityuncommon
Description
This specimen displays a silvery-gray to dark gray metallic mineral with a platy or foliated appearance, embedded within a lighter, possibly quartzose, matrix.
Geological Context
Tetradymite typically forms in hydrothermal veins, often associated with gold deposits and other telluride minerals, in low-temperature to moderate-temperature environments.
