Purpurite

Purpurite is named after Latin "purpura" - purple, referring to its colour.

Purpurite has a striking colour and it would be very popular as a gemstone, if it were not such a rarity.
General Information
Chemical Formula
MnPO
 
4
Walter Schumann, Gemstones of the world (2001)
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Photos of natural/un-cut material from mindat.org
Physical Properties of Purpurite
Mohs Hardness4 to 4.5
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Specific Gravity3.2 to 3.4
Walter Schumann, Gemstones of the world (2001)
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TenacityBrittle
Walter Schumann, Gemstones of the world (2001)
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Cleavage QualityDistinct
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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FractureUneven
Arthur Thomas, Gemstones (2009)
Optical Properties of Purpurite
Refractive Index1.85 to 1.92
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Optical CharacterBiaxial/+
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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Birefringence0.07
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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PleochroismStrong
Arthur Thomas, Gemstones (2009)
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DispersionRelatively strong
Arthur Thomas, Gemstones (2009)
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Colour
Colour (General)Purple, deep pink, dark brown
Walter Schumann, Gemstones of the world (2001)
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TransparencyTranslucent
Walter Schumann, Gemstones of the world (2001)
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LustreMetallic
Walter Schumann, Gemstones of the world (2001)
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Crystallography of Purpurite
Crystal SystemOrthorhombic
Ulrich Henn and Claudio C. Milisenda, Gemmological Tables (2004)
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HabitMassive
Arthur Thomas, Gemstones (2009)
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Geological Environment
Where found:Derived from oxidation and leaching of primary Mn–Fe phosphates, particularly lithiophilite, in complex granite pegmatites; rarely, formed by reaction between bat guano and Fe–Mn deposits resulting from seawater ingress.
Anthony et al, Handbook of Mineralogy (2001)
Further Information
Mineral information:Purpurite information at mindat.org
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