ZEUNERITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Uranyl arsenates
    Crystal system : Tetragonal
    Chemistry : Cu(UO2)2(AsO4)2 16H2O
    Rarity : Rare

Zeunerite is a copper and uranium arsenate. It is a rare secondary mineral that forms in the oxidation zones of uranium and copper deposits. It was named in honor of the German physicist Gustav Anton Zeuner, Director of the Freiberg School of Mines (Germany). Zeunerite forms rare emerald green tabular crystals, quite similar to torbernite. It is a very accessory ore of uranium.

Main photo : Zeunerite from Brumado, Bahia, Brazil © Rock Currier

Zeunerite from Montoso Quarries, Piedmond, Italy © Beppe Finello
Zeunerite from Montoso Quarries, Piedmond, Italy © Franco Luca Bonino
Zeunerite from Clara Mine, Germany © Michael Förch
Zeunerite from Rabejac, Hérault, France © Stephan Wolfsried

Zeunerite in the World

Exceptional 4 cm crystals have been discovered in the Brazilian mine of Pedra Preta near Brumado (Bahia, Brazil). Zeunerite is also reported in the copper-uranium deposits of English Cornwall (Gwennap, St-Just), Germany (Menzenschwand, Schneeberg), and in several American deposits.

Zeunerite in France

In France, zeunerite is known in beautiful small crystals in the mine of Cap Garonne (Var), and in the uranium deposits of Margnac (Haute-Vienne) and Rabejac (Hérault). It is also known in Kergornec (Côtes-d'Armor) and in many other small deposits.

Twinning

No twinning known for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 2.5
Density : 3.47
Fracture : Micaceous
Streak : Yellow-green to green

TP : Translucent to transparent
RI : 1.582 to 1.613
Birefringence : 0.028
Optical character : Uniaxial -
Pleochroism : Visible
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : Strong