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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
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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