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Download hereGENERAL DESCRIPTION
Autunite is a hydrated calcium and uranium phosphate. It is formed in the oxidation zones of the uranium-bearing deposits and in hydrothermal veins. It is an important uranium ore. Autunite often forms encrustations.
The crystals are tabular and be assembled to show a foliation. They are of yellow-lemon to clear green colour. As it is a radioactive mineral, precautions are necessary for the handling and the conservation of autunite.
Autunite is rather present throughout the world as an uranium ore. For the remarkable crystals, one can quote the deposits of the Spessart Mounts in Bavaria; close of Malacacheta in Brazil (crystals of 2,5 cm); the county of Boulder in Colorado and to the Mount Spokane (USA), Setubal (Portugal) and Bergen (Germany).
There are very many French localities, among which Saint-Symphorien of Marmagne (where the first samples were discovered) and the Oudots in the Saone et Loire; St. Priest la Prugne in the Loire or Chaméane in the Puy de Dôme.
The types of this species are kept at the Muséum national d’Histoire naturelle (Paris, France) in the Haüy collection (H6307). The 18 kept sample-types were given by Mr. Champeaux de Saucy, which discovered the first samples of this species. They were discovered at La Ouche d'Jau, close to St Symphorien-de-Marmagne, area of Autun (which gave him its name) in Saone-et-Loire.
HISTORY : Named to recall its type-locality: Autun , Morvan area, France
Species first described in 1852 by Henry James Brooke (1771-1857) and William Hallowes Miller (1801-1880), English mineralogists
Type-locality: Saint Symphorien de Marmagne, Saône et Loire, France
ANCIENT NAME : Urane oxydé, uranite
CHEMICAL FORMULA : Ca (UO2)2 (PO4)2 10 12H2O
CRYSTAL SYSTEM : Tetragonal
COLOR : Lemon yellow to sulfur-like yellow, yellow greenish to green
DIAPHANIETY : Transparent to translucent
LUSTER : Vitreous
STREAK : Light yellow
MORPHOLOGIE : Fine crystals, tabular. As aggregates
HARDNESS : 2,0-2,5
CHEMICAL CLASS: 3,14
DENSITY : VII - Phosphates, arsenates and vanadates
GROUP : Autunite
STRUNZ CLASS BEFORE 2001 : 7/E.01-90
STRUNZ CLASS AFTER 2001 : 8.EB.10
