Uranophane

uranophane

autunite

torbernite

uraninite

Images

Formula: Ca(U6+O2)2(SiO3OH)2.5H2O
Nesosilicate (insular SiO4 groups), uranophane group, uranyl mineral
Crystal System: Monoclinic
Specific gravity: 3.8 to 3.91 measured, 3.78 calculated
Hardness: 2½ to 3
Streak: Yellowish white
Colour: Light yellow, lemon-yellow, honey-yellow, straw-yellow, green-yellow
RADIOACTIVE
Environments:

Pegmatites
Hydrothermal environments

Uranophane occurs in pegmatites, and as an alteration product of uraninite in oxidised uranium deposits (Dana, Webmin). It is the most common uranium silicate mineral, and occurs at practically every locality where pitchblende is found (AM 40.634, HOM). Uranophane is associated with other secondary uranium minerals, including autunite, torbernite, kasolite, schoepite, meta-autunite, phosphuranylite and sklodowskite (AM 40.634, HOM).

Localities

At the Margaritas No. 1 Mine, Sierra Peña Blanca, Peña Blanca District, Aldama Municipality, Chihuahua, Mexico, uranophane crystallised inside cavities lined with glossy dark brown to black material that might be goethite (Mindat photo).
Uranophane from the Margaritas No. 1 Mine - Image

The type Locality is Miedzianka, Gmina Janowice Wielkie, Jelenia Góra Co, Lower Silesian Voivodeship, Poland.
Uranophane from the Miedzianka Field - Image

At Shaba, Zaire, uranophane occurs as pseudomorphs after uraninite and in association with kasolite, rutherfordine and less commonly soddyite (Dana).

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