Purpurite

triphylite

pegmatites

Formula:(Mn3+,Fe3+)(PO4)
Anhydrous normal phosphate, triphylite group, forms a series with heterosite
Specific gravity: 3.2 to 3.4
Hardness: 4 to 4½
Streak: Light to medium purple, lighter than the colour of the massive mineral
Colour: Dark purple to purplish red
Solubility: Soluble in hydrochloric acid
Environments

Pegmatites

Purpurite is a secondary mineral derived from oxidation and leaching of primary manganese-iron phosphates, particularly lithiophilite, in complex granite pegmatites; the purpurite leaches lithium, Li, out of its site, leaving a vacancy, and oxidises divalent manganese Mn2+ to trivalent manganese Mn3+ (HOM, Mindat, Dana).
Rarely, purpurite is formed by reaction between bat guano and iron-manganese deposits resulting from seawater ingress (HOM).
Associated minerals include lithiophilite, sicklerite and many secondary iron-manganese phosphates (HOM).

At the type locality, the Faires Mine, Kings Mountain, Gaston county, North Carolina, USA, purpurite occurs in oxidised and leached primary lithiophilite pods from a granite pegmatite (Mindat).

Common impurities: Fe

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