Brassite
(repeating unit)Mg(AsO3OH)·4(H2O) IMA symbol Bsi[1] Strunz classification 8.CE.15 Dana classification 39.01.07.01 Crystal system Orthorhombic Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m) Space group Pbca Unit cell a = 7.472 Å,
b = 10.891 Å,
c = 16.585 Å; Z = 8 Identification Color White Crystal habit Cryptocrystalline crusts Cleavage {001} Perfect Fracture Irregular/uneven, splintery Tenacity Brittle Luster Silky, dull, earthy Streak White Diaphaneity Translucent Specific gravity 2.28 Optical properties Biaxial (+) Refractive index nα = 1.531 nβ = 1.546 nγ = 1.562 Birefringence 0.031 Pleochroism Non-pleochroic 2V angle 80° Dispersion r < v moderate Solubility +++ HCl, + H2O References [2][3][4][5]
H-M symbol: (2/m 2/m 2/m)
b = 10.891 Å,
c = 16.585 Å; Z = 8
Brassite is a rare arsenate mineral with the chemical formula Mg(AsO3OH)·4(H2O). It was named brassite, in 1973, to honor French chemist R`ejane Brasse, who first synthesized the compound. The type locality for brassite is Jáchymov of the Czech Republic.[3]
It occurs as an alteration of magnesium carbonate minerals by arsenic bearing solutions. It occurs associated with pharmacolite, picropharmacolite, weilite, haidingerite, rauenthalite, native arsenic, realgar and dolomite.[4]
Localities
Czech Republic:
- Jáchymov, Ore Mountains, Karlovy Vary Region, Czech Republic
France:
- Salsigne mine, Salsigne, Mas-Cabardès, Carcassonne, Aude, Languedoc-Roussillon, France
- Villanière (slag locality), Salsigne, Mas-Cabardès, Carcassonne, Aude, Languedoc-Roussillon, France
Germany:
- Wilhelm Mine (Wechselschacht), Bauhaus, Richelsdorf District, Hesse, Germany
- Ore dumps, Richelsdorf Smelter, Süss, Richelsdorf District, Hesse, Germany
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.
- ^ Webmineral.com - Brassite
- ^ a b Mindat.org - Brassite
- ^ a b "Handbook of Mineralogy - Brassite" (PDF). Archived from the original (PDF) on 2016-03-03. Retrieved 2013-01-25.
- ^ Mineralatlas.com - Brassite
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