TUNGSTITE

    Class : Oxides and hydroxides
    Subclass : Hydroxides and hydrates
    Crystal system : Orthorhombic
    Chemistry : WO3 H2O
    Rarity : Rare


Tungstite is a rare hydroxide, resulting from the atmospheric alteration of wolframite and scheelite. It is found in the oxidized surface parts of hydrothermal tungsten deposits (high-temperature veins, skarns, stratoid deposits). Its name comes from its chemical composition. Tungstite usually forms powdery or earthy coatings, more rarely small honey-yellow to bright yellow crystals, rarely greenish yellow.

Main photo : Tungstite from San Antonio de Calacalani mine, Oruro, Bolivia © Thomas Witzke

Tungstite in the World

Beautiful specimens of tungstite have been discovered in the large wolframite vein of Panasqueira (Portugal) and in Tazna (Bolivia).

Tungstite in France

n France, tungstite is known in beautiful samples in the Meymac vein (Corrèze), where it was sometimes called "meymacite". It is also reported in Puy-les-Vignes and in the mines of Vaulry (Haute-Vienne) and Echassières (Allier).

Twinning

No twinning known for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.



Hardness : 2.5
Density : 5.52
Fracture : Undetermined
Streak : Yellow-green


TP : Translucent to transparent
RI : 2.090 to 2.260
Birefringence : 0.170
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : None


Solubility : Bases

Magnetism : NoneRadioactivity : None