Purpurite

Purpurite
Purpurite from Namibia
General
Category	Phosphate minerals
Formula	Mn3+PO4
IMA symbol	Pur [1]
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	Uneven
Tenacity	Brittle
Mohs scale hardness	4–5
Luster	Earthy
Streak	red
Specific gravity	3.2 – 3.4
Optical properties	Biaxial (+)
Refractive index	nα = 1.850(2) nβ = 1.860(2) nγ = 1.920(2)
Birefringence	δ = 0.070
2V angle	38°
References	[2] [3] [4]

Purpurite is a manganese phosphate mineral with the formula 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. ^[3]

Purpurite forms a series with the iron-bearing endmember heterosite, FePO₄. ^[4]

See also

• Manganese violet

References

1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
2. Mineralienatlas
3. "Purpurite". Webminerals. Retrieved 2009-06-06.
4. Mindat