What is Metatorbernite?
Metatorbernite is visually striking but should be treated as a scientific specimen first. Its vivid green plates reveal the chemistry of oxidised uranium deposits and the way hydration state changes the torbernite family.
Mineralogy and crystal structure
Reference formula: Cu(UO2)2(PO4)2·8H2O. Metatorbernite is a tetragonal dehydrated member of the torbernite family, with copper, phosphate and uranyl groups in a layered structure. It is radioactive and can dehydrate, so both storage and handling need specialist care. Metatorbernite is classified with phosphates and has a tetragonal crystal system. Typical hardness is 2–2.5 on the Mohs scale and specific gravity is approximately 3.5–3.7.
Colour, lustre and habit
Typical colours include emerald-green, green, dark green. The usual tabular, platy, crusty habit and vitreous, pearly lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Metatorbernite forms in or is associated with oxidised uranium deposits where copper-bearing fluids interact with phosphate minerals. Important documented localities include France, Germany, the United States, Portugal, the Democratic Republic of the Congo and Australia.
Emerald-green plates from a uranium deposit
Metatorbernite is visually striking but should be treated as a scientific specimen first. Its vivid green plates reveal the chemistry of oxidised uranium deposits and the way hydration state changes the torbernite family.
Collecting and care
Radioactive and toxic as dust: keep sealed, limit handling, avoid cutting or grinding, and use appropriate radiation-safety practice.
