What is Purpurite?
Purpurite is a purple manganese phosphate, valued in lapidary material and mineral collections for saturated colour and a distinctive weathered surface.
Mineralogy and crystal structure
Reference formula: MnPO4. Purpurite is orthorhombic and commonly forms as massive or earthy alteration of lithiophilite. Surface oxidation and manganese chemistry control the purple colour. Purpurite is classified with phosphates and has a orthorhombic crystal system. Typical hardness is 4–4.5 on the Mohs scale and specific gravity is approximately 3.5–3.7.
Colour, lustre and habit
Typical colours include purple, violet, red-purple, brown. The usual massive, botryoidal, crusty habit and dull, earthy, sub-metallic lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Purpurite forms in or is associated with oxidised lithium- and manganese-rich granite pegmatites. Important documented localities include Namibia, Portugal, the United States, Brazil and Australia.
Purple colour from a weathered pegmatite
Purpurite turns pegmatite alteration into colour. Its deep purple surface is both a commercial draw and a clue to manganese-phosphate chemistry.
Collecting and care
Avoid acids and abrasion; keep dry and preserve a fresh edge or matrix for identification.
