What is Native Platinum?
Native platinum is a dense cubic platinum-group metal found in ultramafic rocks and placer deposits, prized for rarity and exceptional heft.
Mineralogy and crystal structure
Reference formula: Pt. Native platinum is cubic and commonly occurs as grains or nuggets with iron, iridium, osmium and other platinum-group substitutions. Its high density and resistance to corrosion are more diagnostic than colour. Native Platinum is classified with elements and has a cubic crystal system. Typical hardness is 4–4.5 on the Mohs scale and specific gravity is approximately 14–19.
Colour, lustre and habit
Typical colours include steel-grey, silver-grey, black. The usual granular, nugget, massive habit and metallic lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Native Platinum forms in or is associated with mafic and ultramafic igneous rocks, chromitites and resistant placer concentrates. Important documented localities include Russia, Colombia, South Africa, Canada, the United States and Ethiopia.
A metal nugget from mantle-derived rock
Native platinum carries the geological signature of ultramafic magma and weathering-resistant metal grains. Its understated grey colour is balanced by extraordinary density and scarcity.
Collecting and care
Very dense and metallic; protect specimens from scratching and retain assay or locality information when available.
