Grundmannite
Grundmannite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula CuBiSe₂.
It crystallizes in the orthorhombic crystal system (space group Pnma). It is a member of the Chalcostibite structural group.
Key properties: Mohs hardness 2–2.5; specific gravity 6.582; Black streak; Metallic luster.
IMA symbol Gdm, IMA status: approved, named in 2015.
A primary mineral, deposited from oxidizing low-temperature hydrothermal fluids at the waning stage of selenide formation in a telethermal vein.
It is found associated with Watkinsonite, clausthalite, krut’aite-penroseite.
The mineral was named to honor Günter Grundmann (b. 1947), for his pioneering work on the El Dragón mine.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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