Tsumcorite | |
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![]() Tsumcorite from the Tsumeb Mine, Namibia | |
General | |
Category | Arsenate minerals |
Formula (repeating unit) | PbZnFe2+(AsO4)2.H2O |
IMA symbol | Tmc[1] |
Strunz classification | 8.CG.15 |
Dana classification | 40.02.09.01 |
Crystal system | Monoclinic |
Crystal class | Prismatic (2/m) (same H-M symbol) |
Space group | C2/m (no. 12) |
Unit cell | a = 9.124 Å, b = 6.329 Å c = 7.577 Å; β = 115.3°; Z = 2 |
Identification | |
Formula mass | 624.29 g/mol |
Color | Yellow-brown, red-brown, orange |
Crystal habit | Radiating, fibrous crusts |
Twinning | Common, on an unknown law |
Cleavage | Good on {001} |
Mohs scale hardness | 4+1⁄2 |
Luster | Vitreous |
Streak | Yellow |
Diaphaneity | Translucent |
Specific gravity | 5.2 |
Optical properties | Biaxial |
Refractive index | nα = 1.87–1.91 nβ = 1.89–1.93 nγ = 1.92–1.96 |
Pleochroism | Weak, yellow to yellow-green |
2V angle | 67–83.5° |
Solubility | Dissolves in HCl |
References | [2][3][4][5][6][7] |
Tsumcorite is a rare hydrated lead arsenate mineral that was discovered in 1971, and reported by Geier, Kautz and Muller.[6] It was named after the TSUMeb CORporation mine at Tsumeb, in Namibia, in recognition of the Corporation's support for mineralogical investigations of the orebody at its Mineral Research Laboratory.[5]