Autunite

specimen number:
2351065

location:
Margnac Mine, Compreignac, Haute Vienne, France

description:

Brilliant bright yellow green platy crystals of autunite to 0.3 cm in size covering one side of this matrix. Brightly fluorescent, in very good condition. Classic locality for the species.

Located in the Haute-Vienne department of the Limousin region in central France, the Margnac Mine at Compreignac is a famous historic uranium deposit hosted within Hercynian granitic basement rocks. The geology features complex veins and episyenite structures that underwent intense hydrothermal alteration, creating ideal conditions for primary uranium ore precipitation alongside a rich diversity of secondary oxidation minerals. Discovered in the mid-20th century during France's postwar atomic energy expansion, the site was intensively exploited underground by CEA and Cogema from the 1950s until operations ceased in the 1990s. Beyond its commercial industrial importance, the mine gained worldwide renown among mineral collectors for yielding exceptionally fine specimens of rare oxidized uranium species, including type-locality agrinierite, as well as bright yellow uranophane crystals and compressed metatorbernite plates.

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