Class : Sulfides and sulfosalts
    Subclass : Sulfides
    Crystal system : Cubic
    Chemistry : Cu₁₂As₄S₁₃
    Rarity : Fairly common

Tennantite belongs, with tetrahedrite and freibergite, to the group of gray coppers: it constitutes the arsenic pole of the continuous solid solution that it forms with tetrahedrite. It has two main varieties : annivite, rich in bismuth and binnite, rich in silver and zinc. It is a hydrothermal mineral particularly abundant in copper deposits rich in arsenic, such as the acid epithermal veins of recent mountain ranges, and porphyry deposits. Its silver contents are lower and rarer than tetrahedrite. It was named in honor of the English chemist Smithson Tennant who discovered osmium and iridium. Tennantite is much less common than tetrahedrite and also less well crystallized. It is most often found in steel gray to black masses, with a strong metallic luster. Its crystals are generally tetrahedral, sometimes cubic, or can have an almost spherical habitus, very rich in faces (binnite facies). It is an important copper ore in certain deposits.

Main photo : Tennantite and pyrite from Tsumeb, Namibia © Neal Luppescu

Twinning on {111} are known.

No fakes listed for this mineral species.