What is Oxyplumboroméite?
Oxyplumboroméite is a lead-rich roméite-group oxide from oxidised antimony deposits, with dense chemistry and a characteristic cubic framework.
Mineralogy and crystal structure
Reference formula: Pb2Sb2O7. Oxyplumboroméite is a complex oxide whose natural chemistry commonly includes substitutions and vacancies. The COD model is a representative cubic roméite framework rather than a guarantee of every sample's exact occupancy. Oxyplumboroméite is classified with oxides and has a cubic crystal system. Typical hardness is 5–6 on the Mohs scale and specific gravity is approximately 5.5–6.2.
Colour, lustre and habit
Typical colours include yellow, orange, brown, black. The usual octahedral, cubic, massive habit and vitreous, resinous lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Oxyplumboroméite forms in or is associated with supergene oxidation of antimony- and lead-bearing hydrothermal deposits. Important documented localities include Italy, France, Germany, Mexico, Australia and South Africa.
Dense yellow oxide in an oxidised vein
The bright surface of oxyplumboroméite can conceal a heavy lead-rich composition. Its cubic structure makes it a useful gateway to the chemistry of supergene antimony deposits.
Collecting and care
Keep sealed and dry; avoid dust, acids, grinding and jewellery use, and handle lead-antimony specimens responsibly.
