Mineral: Torbernite
Locality: Chaméane Uranium Deposit, Le Vernet-Chaméane, Issoire District, Puy-de-Dôme Department, Auvergne-Rhône-Alpes, France
Dimensions: FOV 1mm

Description: Tabular green torbernite crystals arranged aesthetically at the edge of a cavity on an amethystine smoky quartz matrix from the Chaméane Uranium Deposit. [The deposit at Chaméane was only mined for uranium for a short period of time and most traces of former workings at the locality have all but disappeared today. Chaméane became particularly notable when three new selenides (chaméanite, geffroyite, giraudite) were discovered there. The uranium mineralisation occurs in altered granite with uraninite (formerly called pitchblende) as the main mineral. Near Chaméane, the subsoil was exploited between 1964 and 1965 for uranium. This operation, carried out in underground mining works, provided 230 tons of ore with a grade equal to 1.33%, which represents approximately 300 kg of uranium. This ephemeral uranium deposit was part of the C.E.A. (Commissariat a l’Energie Atomique) geological survey of the Forez Tertiary plain (in the French ‘Massif Central’) which delivered 7,000 tons of uranium. The ore was essentially made up of uraninite and gummite (a yellow amorphous mixture of uranium minerals, oxides, silicates, and hydrates of uranium, derived from alteration of uraninite). The Chaméane deposit also delivered some amethyst, although specimens are better known from the neighbouring former commune of Vernet-la-Varenne where artisanal mining of this purple variety of quartz used to be quite active.]

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