Arsenoclasite
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Arsenoclasite (originally arsenoklasite) is a red or dark orange brown mineral with formula Mn5(AsO4)2(OH)4. The name comes from the Greek words αρσενικόν (for arsenic) and κλάσις (for cleavage), as arsenoclasite contains arsenic and has perfect cleavage.[1] The mineral was discovered in 1931 in Långban, Sweden.
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Arsenoclasite | |
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General | |
Category | Arsenate mineral |
Formula (repeating unit) | Mn5(AsO4)2(OH)4[1] |
IMA symbol | Asc[2] |
Strunz classification | 8.BD.10[1] |
Dana classification | 41.4.1.1[1] |
Crystal system | Orthorhombic[1] |
Crystal class | Disphenoidal (222) H-M symbol: (222) |
Space group | P212121[3] |
Unit cell | a = 9.31, b = 5.75 c = 18.29 [Å];[1] Z = 4[3] |
Identification | |
Formula mass | 620.56 g/mol[4] |
Color | Red, dark orange-brown[3] |
Crystal habit | Massive or granular[1] |
Cleavage | Perfect on {010}[3] |
Mohs scale hardness | 5–6[1] |
Diaphaneity | Translucent[3] |
Density | 4.16 g/cm3 (measured)[1] |
Optical properties | Biaxial (−)[1] |
Refractive index | nα = 1.787, nβ = 1.810, nγ = 1.816[1] |
Birefringence | δ = 0.029[1] |
2V angle | 53°[1] |
Dispersion | Extreme[1] |
References | [1][3][4][5] |
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