_Uranocircite _Uranium minerals (despite their radioactivity and toxicity) tend to have vivid and pr
_Uranocircite _Uranium minerals (despite their radioactivity and toxicity) tend to have vivid and pretty colours and nice forms making for attractive mineral specimens much desired in collections, despite their special storage and handling needs. They are also very soft and flaky so caution must be exercised when handling them and the hands thoroughly washed afterwards. The example in the photo is a barium uranium phosphate containing water in its structure, and commonly occurring in bright yellows and greens.The name comes from the Greek for falcon (and the associated goddess Circe), since it was discovered in Falkenstein (falcons stone) in Germany. It is a secondary mineral, formed by alteration of primary ones by the chemical action of the waters within the Earth, and it is usually found in quartz veins. It is rare, but popular among collectors due to its beauty. Crystals are commonly square to tabular, but bladed spray like aggregates such as this one and crusts are also common.It converts to meta-uranocircite as it inevitably dehydrates, losing the water holding the plates together, and it should therefore be stored in a sealed container away from humidity and at a safe distance from other minerals in the collection since the radioactivity might affect their colour. These specimens are best only handled occasionaly.Uranium minerals are also commonly fluorescent, emitting visible light when exited by the higher energy wavelengths of ultraviolet which bumps electrons up a shell within the atom. The visible light is emitted when the electron returns to its normal rest state due to the law of conservation of energy. Uranocircite’s glow is a bright green. Sources include Bergen in Germany, Brazil, Cornwall, the USA, Zaire/DRC and France. The specimen in the photo comes from Minas Gerais in Brazil, and measures 3.7 x 3.5 x 3.1 cm.LozDear Readers, Most of our posts are not reaching you in your news feed due to fb’s filtering system. If you wish to enjoy our posts more often, use the following for information on how to go about it: http://tinyurl.com/qgwac8k.Image credit: Rob Lavinsky/iRocks.comhttp://www.dakotamatrix.com/mineralpedia/7348/uranocircitehttp://www.galleries.com/Uranocircitehttp://www.mindat.org/min-4105.htmlhttp://webmineral.com/data/Uranocircite.shtml#.VGul68lQBZ4 -- source link
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