Braunite
Nesosilicate mineral of manganese
6+1⁄2Braunite is a silicate mineral containing both di- and tri-valent manganese with the chemical formula: Mn2+Mn3+6[O8|SiO4].[3] Common impurities include iron, calcium, boron, barium, titanium, aluminium, and magnesium.
Braunite forms grey/black tetragonal crystals and has a Mohs hardness of 6 – 6.5.
It was named after the Wilhelm von Braun (1790–1872) of Gotha, Thuringia, Germany.[3]
A calcium iron bearing variant, named braunite II (formula: Ca(Mn3+,Fe3+)14SiO24), was discovered and described in 1967 from Kalahari, Cape Province, South Africa.[4][5]
References
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Mineralienatlas
- ^ a b Mindat
- ^ JoHan P. R. De Viliers, The crystal structure of braunite II and its relation to bixbyite and braunite, American Mineralogist, Volume 65, pages 756–765, 1980
- ^ Mindat, Braunite-II
External links
- Webmineral
- Athena mineral
Wikimedia Commons has media related to Braunite.
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Manganese minerals
- Sussexite
- Tusionite
- Ankerite
- Kutnohorite
- Rhodochrosite
- Manganoan calcite
| Simple | |
|---|---|
| Mixed |
- Axinite (borosilicate)
- Geigerite (arsenate)
- Manganese nodule (various)
- Samsonite (sulfosalt)
- Zincobotryogen (sulfate)
- Wolframite (tungstate)
- Hübnerite (tungstate)
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