Bismite . Pen for scale. No locality given. Mineral collection of Brigham Young University Department of Geology, Provo, Utah. Photograph by Andrew Silver. BYU index 4-8051, Bi_2O_3. — Photo: Photograph by Andrew Silver · Public domain
Bismite
Bismuth trioxide — a monoclinic oxide that usually appears as greenish-yellow clay-like masses rather than crystals.
Intro adapted from Wikipedia (CC BY-SA).
Bismite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Bi₂O₃.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 4.5; specific gravity 8.64–9.22; Gray to yellow streak; Subadamantine to dull, earthy luster; optically biaxial.
IMA symbol Bis, grandfathered status — known before the IMA’s founding, named in 1868.
An oxidation product of bismuth.
It is found associated with Bismuth, bismutite, cassiterite.
The name refers to BISMuth in its composition.