Metatorbernite, copper uranyl phosphate,
Formula Cu(UO2)2(PO4)2.8H2O.


Metatorbernite is a secondary mineral formed by the dehydration of torbernite during weathering. It only occurs directly above 75 degrees Centigrade. Metatorbenite distribution is widespread, occurring wherever torbernite is found. A primary deposit of Metatorbernite in the UK is found at the Gunnislake mine at Calstock in Cornwll.

The prefix 'meta' in a mineral name implies a lower level of water. Metatorbernite has eight water molecules whereas torbernite has eight to twelve water molecules.

The specimen shown in the picture comes from Margabal, Entraygue, Averyon, France.

Metatorbernite from Margabal, Entraygue, Averyon, France