Formula: (H3O)(UO2)(PO4).3H2O
Hydrated normal phosphate, meta-autunite group
Specific gravity: 3.259 (Russian samples, Dana), 3.399 (synthetic, AM 40.917-919)
Hardness: 2 to 2½
Streak: Yellowish white
Colour: Pale yellow

Plutonic igneous environments

Chernikovite is a rare uranium mineral which is easily transformed into parsonsite (Dana).


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).

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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