UMANGITE

    Class : Sulfides and sulfosalts
    Subclass : Selenides
    Crystal system : Tetragonal
    Chemistry : Cu3Se2
    Rarity : Very rare

Umangite is an extremely rare copper selenide found in hydrothermal deposits containing selenium, most often uranium veins. Its name comes from its discovery location : Sierra de Umango (Argentina). Umangite is a usually xenomorphic mineral forming only small grains, with a roughly rectangular outline, of a bluish-black to reddish tint fading to a dark iridescent purple. It is a potential source of selenium.

Main photo : Umangite from the Clara mine, Germany © Michael Förch

Umangite in the World

Umangite is present associated with other selenides (clausthalite, eskebornite) and often with uraninite in several hydrothermal veins of the Harz in Germany (Clausthal, Tilkerode, St-Andréasberg, etc...) and in the Czech Republic, mainly in Bukov and Petrovice. It is also present associated with chalcopyrite and berzelianite in the Skrikerum copper mine (Sweden) and in Argentina in the Sierra Cacheuta and in the Sierra Umango. Umangite is also known in the large uranium deposits of Uranium City (Lake Athabasca, Canada) and in the inevitable deposits of Tsumeb (Namibia) and Shinkolobwe (Democratic Republic of Congo).

Umangite in France

In France, umangite is known in the small pitchblende selenide vein of Chaméane (Puy-de-Dôme) as well as in the uranium deposit of Kruth (Haut-Rhin).

Twinning

Lamellar twinning is known.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 3
Density : 6.44 to 6.49
Fracture : Irregular to sub-conchoidal
Streak : Black

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

Solubility : Nitric acid

Magnetism : NoneRadioactivity : None