Purpurite | |
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General | |
Category | Phosphate minerals |
Formula (repeating unit) |
Mn3+PO4 |
Strunz classification | 8.AB.10 |
Crystal system | Orthorhombic |
Crystal class | Dipyramidal (mmm) H-M symbol: (2/m 2/m 2/m) |
Space group | Pnmb |
Identification | |
Formula mass | 149.91 g/mol |
Color | Brownish black, violet, dark pink, dark red, reddish purple |
Crystal habit | Massive to granular |
Cleavage | [100] [001] perfect |
Fracture | Brittle - uneven |
Mohs scale hardness | 4-5 |
Luster | Earthy |
Streak | red |
Specific gravity | 3.2 - 3.4 |
Optical properties | Biaxial (+) 2V 38° |
Refractive index | nα = 1.850(2) nβ = 1.860(2) nγ = 1.920(2) |
Birefringence | δ = 0.070 |
Other characteristics | non-radioactive, non-magnetic, non-fluorescent. |
References |
Purpurite is a mineral, manganese phosphate, MnPO4 with varying amounts of iron depending upon its source. Like many manganese-containing minerals, it is a striking pink purple color.
Purpurite forms a series with the iron-bearing endmember heterosite, FePO4.