Umangite

Umangite is a copper selenide mineral, Cu3Se2, discovered in 1891. It occurs only in small grains or fine granular aggregates with other copper minerals of the sulfide group. It has a hardness of 3. It is blue-black to red-violet in color with a black streak. It has a metallic luster. Umangite is named after the locality of Sierra de Umango, La Ri...
Found on http://en.wikipedia.org/wiki/Umangite

umangite

a copper selenide (Cu3Se2) occurring only in small grains or fine granular aggregates with other copper minerals of the sulfide group. The mineral ...
Found on http://www.britannica.com/eb/a-z/u/5
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