STANNITE

    Class : Sulfides and Sulfosalts
    Subclass : Sulfides
    Crystal system : Tetragonal
    Chemistry : Cu2FeSnS4
    Rarity : Fairly common

Stannite is the most common of the tin sulfides. It is a fairly common hydrothermal mineral found in pneumatolytic deposits and high-temperature hydrothermal deposits as well as in Andean deposits. Its name comes from the Latin stannum (tin) in reference to its chemical composition. Stannite has a metallic luster and a steel-gray color with a greenish tinge. It generally occurs in granular masses, usually alongside chalcopyrite, cassiterite, and arsenopyrite. It is an accessory ore of tin.

Main photo : Stannite on arsenopyrite from Yaogangxian Mine, Hunan, China © Eugene & Sharon Cisneros

Stannite from Itos Mine, Oruro, Bolivia © Rock Currier
Twinned stannite from San José Mine, Oruro, Bolivia © Kelly Nash
Stannite from Yaogangxian Mine, Hunan, China © Neal Luppescu
Stannite from Vaulry, Haute-Vienne, France © Alain Tuel

Stannite in the World

Stannite crystals are very rare. The best of these, 3 cm specimens associated with arsenopyrite, chalcopyrite, muscovite and quartz were discovered at Yaogangxian (Hunan, China). Before this discovery, all the beautiful stannite crystals came from the tin deposits of Bolivia : the most aesthetic were extracted from the mining districts of Oruro (spheroidal clusters of crystals measuring 3 cm in the San José mine), and Llallagua (45 mm crystals on pyrite in the Salvadora vein). The mines of English Cornwall have also allowed the extraction of interesting specimens.

Stannite in France

In France, stannite is present in the high-temperature veins of Vaulry (Haute-Vienne). It is also reported at Echassières (Allier), Salsigne (Aude), Montebras (Creuse) as well as in many other deposits.

Twinning

Interpenetration twinning is known on {102}, around {112} and with {112} as the composition plane.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 4
Density : 4.3 to 4.5
Fracture : Irregular
Streak : Black

TP : Opaque
RI : -
Birefringence : -
Optical character : -
Pleochroism : None
Fluorescence : None

Solubility : Nitric acid

Magnetism : NoneRadioactivity : None