Formula: (H3O)(UO2)(PO4).3H2O
Hydrated normal phosphate, uranyl mineral,
meta-autunite group
Crystal System: Tetragonal
Specific gravity: 3.259 measured, 3.261 calculated
Hardness: 2 to 2½
Streak: Yellowish white
Colour: Pale yellow
Environments
Plutonic igneous environments
Pegmatites
Chernikovite is a rare uranium mineral which is easily transformed
into parsonsite
(Dana).
Localities
At Perus, São Paulo, Brazil, chernikovite occurs as inclusions in
autunite and meta-autunite,
along fractures in tourmaline-bearing
granite and granite
pegmatites. Associated minerals include
autunite,
meta-autunite, uranophane,
uranophane-β,
phosphuranylite,
torbernite, metatorbernite,
haiweeite and uranian opal
(HOM, AM 74.1400-1401).
Chernikovite from Perus - Image
At the type locality, Karakat U Deposit, Karamazar mountains, Adrasman, Sughd, Tajikistan, chernikovite occurs
in fissures in quartz syenite
and around fossil wood, associated with autunite,
meta-autunite and
metanatroautunite
(HOM).
At the Werner Number 4 pit, Mayfield, Fulton county, New York, USA, chernikovite was found in a pegmatite body,
occurring as millimeter-sized crystals along cleavages and fractures in
microcline. It is suggested that the mineral replaced
autunite, probably during a late low-temperature hydrothermal phase
(R&M 89.6.542).
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