Purpurite is a mineral, manganese phosphate, MnPO4 with varying amounts of iron depending upon its source. It occurs in color ranges from brownish black via purple and violet to dark red.[2]
| Purpurite |
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 Purpurite from Namibia |
| General |
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| Category | Phosphate minerals |
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Formula
(repeating unit) | Mn3+PO4 |
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| Strunz classification | 8.AB.10 |
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| Crystal system | Orthorhombic |
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| Crystal class | Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m) |
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| Space group | Pnmb |
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| Identification |
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| Formula mass | 149.91 g/mol |
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| Color | Brownish black, violet, dark pink, dark red, reddish purple |
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| Crystal habit | Massive to granular |
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| Cleavage | [100] [001] perfect |
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| Fracture | Brittle - uneven |
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| Mohs scale hardness | 4-5 |
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| Luster | Earthy |
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| Streak | red |
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| Specific gravity | 3.2 - 3.4 |
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| Optical properties | Biaxial (+) 2V 38° |
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| Refractive index | nα = 1.850(2) nβ = 1.860(2) nγ = 1.920(2) |
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| Birefringence | δ = 0.070 |
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| Other characteristics | non-radioactive, non-magnetic, non-fluorescent. |
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| References | [1][2][3] |
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Purpurite forms a series with the iron-bearing endmember heterosite, FePO4.