What is Umangite?
Umangite is a rare copper selenide with deep red to violet-red colour, found in low-temperature selenium-rich hydrothermal ore assemblages.
Mineralogy and structure
Reference formula: Cu3Se2. Umangite is tetragonal and commonly occurs as granular or massive material with other copper selenides. The exact COD 1528745 model supports the structure page; colour alone is not sufficient for identification. Umangite is classified with selenides and has tetragonal crystal symmetry. Typical hardness is 2.5–3 on the Mohs scale and specific gravity is approximately 5.7–5.9.
Colour, lustre and habit
Typical colours include dark red, violet-red, grey, black. The usual granular, massive, crusty habit and metallic, sub-metallic lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Umangite forms in or is associated with selenium-rich hydrothermal veins, oxidised copper deposits and low-temperature ore cavities. Important documented localities include Germany, the Czech Republic, Bolivia, Mexico and the United States.
A rare red selenide from a copper vein
Umangite appeals to collectors who value unusual chalcogen chemistry: its dark red colour is a visual clue to a selenium-rich ore system, especially when the matrix and association are documented.
Collecting and care
Keep enclosed and avoid dust, acids and cutting. Selenium- and copper-bearing material should be handled as an ore specimen and not used for jewellery or casual contact.
