Černýite
Černýite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Cu₂CdSnS₄.
It crystallizes in the tetragonal crystal system (space group I-42m). It is a member of the Sphalerite, Stannite structural group.
Key properties: Mohs hardness 4; specific gravity 4.776; Black streak; Metallic. Anisotropism: Very weak in shades of gray. R1 –R2: (470) 24.6 and 25.5, (546) 23.4 and 25.6 luster.
IMA symbol Čný, IMA status: approved, named in 1976.
A rare constituent of complex zoned pegmatites, as a component of a very minor sulfide mineral suite.
It is found associated with Pyrrhotite, sphalerite, hawleyite, chalcopyrite, stannite, bismuth, kësterite.
The mineral was named to honor Dr. Petr Černý (1934–), Czech-Canadian mineralogist specializing in pegmatites, University of Manitoba, Winnipeg, Canada.