- Zippeite
Zippeite is a hydrous
potassium uranium sulfate mineral with formula: K4(UO2)6(SO4)3(OH)10·4(H2O). It forms yellow to reddish brownmonoclinic -prismatic crystals with perfect cleavage. The typical form is as encrustations and pulverulent earthy masses. It forms as efflorescent encrustations in underground uranium mines. It has aMohs hardness of 2 and aspecific gravity of 3.66. It is stronglyfluorescent yellow in UV radiation and is aradioactive mineral.Historical usage
A mineral which caught the attention of a
Bohemian metallurgist,Adolf Patera in the 1850s by its striking colour. This was during the period when the fame of theJachymov silver mines was dying out. On top of the large, forgotten pit-heaps, powdery minerals began to appear, vividly coloured, originating from the decomposition of the pitchblende. These colourful layers, in which zippeite was in the majority, gavePatera the idea of utilizing the uranium minerals in the manufacture of paints. Mining began in 1859 not only for the products which resulted from uraninite's decomposition, but for uraninite itself. A variety of yellow paints were manufactured because among all the secondary minerals on the pit-heap there was a prevalence of the yellow powdery coatings.Zippeite is one of the so-called 'uranium ochres'. It occurs in association with uranopilite, a monoclinic, complex water-soluble alkaline with other secondary uranium minerals in the weathered veins of uranium. It was named after the
Prague minerologist,F. X. M. Zippe (1791-1863). Apart from Jachymov inBohemia it occurs mainly nearWolsendorf inBavaria (Germany ) and also inUtah (U.S.). Zippeite is no longer used for the manufacture of paints. It is used as a uranium ore, as is pitchblende.References
* Palache, C., H. Berman, and C. Frondel (1951) "Dana’s System of Mineralogy," (7th edition), v. II, 598–599.
* [http://www.webmineral.com/data/Zippeite.shtml Webmineral data]
* [http://www.mindat.org/min-4420.html Mindat]
* [http://www.uraniumminerals.com/UTh/Zippeite.htm Uranium minerals]
* [http://mineral.galleries.com/minerals/sulfates/zippeite/zippeite.htm Mineral galleries]
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