Autunite
Encyclopedia
Autunite with formula: Ca(UO2)2(PO4)2·10-12H2O is a yellow - greenish fluorescent mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...

 with a hardness of 2 - 2½. Autunite crystallizes in the tetragonal system and often occurs as tabular square crystals. Due to the moderate uranium
Uranium
Uranium is a silvery-white metallic chemical element in the actinide series of the periodic table, with atomic number 92. It is assigned the chemical symbol U. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons...

 content of 48.27% it is radioactive and also used as uranium ore. If the mineral dries out, it converts to meta-autunite-I, which can turn into meta-autunite-II after heating. These two subsequent minerals are very rare in nature. For scientific studies it is recommended to store the mineral in a sealed container to minimize the water loss. Museums are known to have covered the mineral with lacquer
Lacquer
In a general sense, lacquer is a somewhat imprecise term for a clear or coloured varnish that dries by solvent evaporation and often a curing process as well that produces a hard, durable finish, in any sheen level from ultra matte to high gloss and that can be further polished as required...

 to avoid drying of the mineral.
Autunite was discovered in 1852 near Autun
Autun
Autun is a commune in the Saône-et-Loire department in Burgundy in eastern France. It was founded during the early Roman Empire as Augustodunum. Autun marks the easternmost extent of the Umayyad campaign in Europe.-Early history:...

, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

.

Mining

Some autunite is found near the Mount Spokane, Washington. 90,000 lbs of U3O8 were produced from nine properties, although most
of the ore came from the Daybreak Mine. The digital geologic map of Spokane county and vicinity show where the autunite is extracted.
Google earth:
lat: 47.885306° long:-117.175846°

Gallery


Image:Autunite UV(AB) France.jpg|Autunite under UV light
Image:Autunite09.jpg|Scaly Crystals of the secondary uranium phosphate mineral Autunite
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