Bismutite Locality: Point 14.0, Hohenstein, Reichenbach, Bensheim, Odenwald, Hesse, Germany Yellow acicular crystals of Bismutite. Field of view 5 mm. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0
Bismutite
A bismuth carbonate that forms where bismuthinite or native bismuth oxidizes in veins and pegmatites.
Intro adapted from Wikipedia (CC BY-SA).
Bismutite is an IMA-recognized mineral species in the carbonate class, with the chemical formula Bi₂O₂(CO₃).
It crystallizes in the orthorhombic crystal system (space group Imm2). It is a member of the Bismutite structural group.
Key properties: Mohs hardness 2.5–3.5; specific gravity 6.1–7.7; Gray streak; Vitreous, waxy, may be dull to earthy luster; refractive index 2.165; optically uniaxial.
IMA symbol Bit, grandfathered status — known before the IMA’s founding, named in 1841.
A relatively common alteration product of other bismuth-bearing minerals in hydrothermal mineral deposits and granite pegmatites.
It is found associated with Bismuth, bismuthinite, tetradymite, many other bismuth-bearing minerals.
In allusion to bismuth in the composition.