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Formula: NiAl4(SO4)(OH)12(H2O)3
Hydrated sulphate containing hydroxyl, chalcoalumite group,
nickel-bearing mineral
Crystal System: Monoclinic
Specific gravity: 2.231 calculated
Hardness: 2
Streak: White
Colour: Colourless to blue to pistachio-green
Luminescence: No fluorescence under UV
Solubility: soluble in hot 1:1 hydrochloric acid
Environments
Metamorphic environments
Hydrothermal deposits
Cave deposits
Localities
At the type locality, the Kara-Tangi U deposit, Batken Region, Kyrgyzstan, nickelalumite occurs as pale-blue to
greenish crusts of radiating lamellar aggregates of crystals up to 1.5 mm on the surface of
uranium-vanadium bearing
carbon-rich siliceous schist formed by hydrothermal alteration.
Associated minerals include quartz,
calcite, alumohydrocalcite,
kyrgyzstanite,
ankinovichite and böhmite
(Mindat).
At the Mbobo Mkulu Cave, Mbombela, Mbombela Local Municipality, Ehlanzeni District Municipality, Mpumalanga, South
Africa, mbobomkulite,
hydrombobomkulite and nickelaluminite have been found as
sky-blue, friable nodules in a matrix of powdery allophane.
Nickelalumite, associated with chalcoalumite also occurs as
thin, pale-blue coatings on gypsum crystals that form a crust on the ceiling
(AM 67.415-416).
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