Brassite

(repeating unit)Mg(AsO3OH)·4(H2O)IMA symbolBsi[1]Strunz classification8.CE.15Dana classification39.01.07.01Crystal systemOrthorhombicCrystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)Space groupPbcaUnit cella = 7.472 Å,
b = 10.891 Å,
c = 16.585 Å; Z = 8IdentificationColorWhiteCrystal habitCryptocrystalline crustsCleavage{001} PerfectFractureIrregular/uneven, splinteryTenacityBrittleLusterSilky, dull, earthyStreakWhiteDiaphaneityTranslucentSpecific gravity2.28Optical propertiesBiaxial (+)Refractive indexnα = 1.531 nβ = 1.546 nγ = 1.562Birefringence0.031PleochroismNon-pleochroic2V angle80°Dispersionr < v moderateSolubility+++ HCl, + H2OReferences[2][3][4][5]

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:

France:

Germany:

  • Wilhelm Mine (Wechselschacht), Bauhaus, Richelsdorf District, Hesse, Germany
  • Ore dumps, Richelsdorf Smelter, Süss, Richelsdorf District, Hesse, Germany

References

  1. ^ 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.
  2. ^ Webmineral.com - Brassite
  3. ^ a b Mindat.org - Brassite
  4. ^ a b "Handbook of Mineralogy - Brassite" (PDF). Archived from the original (PDF) on 2016-03-03. Retrieved 2013-01-25.
  5. ^ Mineralatlas.com - Brassite
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