Metatorbernite, copper uranyl phosphate,
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.