Krut'aite
A rare cubic copper diselenide of the pyrite group.
Intro adapted from Wikipedia (CC BY-SA).
Krut'aite is an IMA-recognized mineral species in the sulfide class, with the chemical formula CuSe₂.
It crystallizes in the cubic crystal system (space group Pa3). It is a member of the Pyrite structural group.
Key properties: specific gravity 6.53; Metallic. Anisotropism: Zones rich in Co and Ni are anisotropic in yellow-brown tints. R: (400) 33.8, (420) 34.2 luster.
IMA symbol Krt, IMA status: approved, named in 1972.
Hydrothermal in origin.
It is found associated with Clausthalite, eskebornite, uraninite, hematite, ferroselite, bukovite, umangite, berzelianite, chalcopyrite, goethite.
The name refers to Dr. Tomáš Kruťa (1906–), Director of the Mineralogy Laboratory, Moravian Museum, Brno, Czech Republic.