Ningyoite

ningyoite

enstatite

montmorillonite

saleeite

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Formula: (U,Ca,Ce)2(PO4)2.1-2H2O
Hydrated phosphate
Crystal System: Orthorhombic
Specific gravity: 4.75
Hardness: 3 to 4
Colour: Brownish green to brown
RADIOACTIVE
Environments

Sedimentary environments

Localities

The Blizzard Uranium deposit and the Tyee deposit, both at Kelowna, Greenwood Mining Division, British Columbia, Canada. Uranium mineralisation in the Blizzard and Tyee deposits occurs as grain coatings and void fillings of ningyoite, saléeite, autunite and pitchblende in a continental conglomerate-sandstone-mudstone sequence. The deposits were formed within a quartz-monzonite/syenite/granodiorite intrusive complex. Ningyoite is the only uranium-bearing mineral identified in the Tyee deposit, where it occurs in close association with marcasite and organic material in conglomerates. In the Blizzard deposit, which consists principally of an assemblage of sandstone, siltstone and mudstone, ningyoite is concentrated principally in siltstone and sandy mudstone. It may also form at sandstone-mudstone interfaces in association with saléeite and organic matter. Pitchblende has been identified in only a few samples from the Blizzard deposit; ningyoite is the main uranium mineral (CM 19.325-331). Other associated minerals include saléeite and autunite (HOM).

At the type locality, the Ningyo-toge mine, Tottori Prefecture, Japan, ningyoite occurs in a conglomerate that overlies the eroded surface of granite. The pebbles are mainly granite and andesitic rocks. Ningyoite occurs in the unoxidised zone, usually as a thin coating on pyrite and apatite or filling cavities, especially in the matrices of the conglomerate or on the surface and along the cracks of the pebbles. Minerals associated with ningyoite include pyrite, marcasite, sphalerite, apatite, chlorite, gypsum, quartz, feldspar, enstatite-ferrosilite, biotite, rutile, calcite, kaolinite and montmorillonite. At least the first six minerals seem to have been brought in after the sedimentation along with ningyoite, which is apparently the last phase except for gypsum (AM 44.633-650).

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