Autunite

phosphate

uraninite

Formula: Ca(UO2)2(PO4)2.10-12H2 hydrated normal phosphate
Specific gravity: 3.2
Hardness: 2 to 2½
Streak: White to yellowish
Colour: Yellow, due to the uranyl ion UO2+2 (Mindat)
Solubility: Autunite is moderately soluble in hydrochloric, sulphuric and nitric acid
Environments:

Pegmatites
Hydrothermal environments

Autunite is a secondary mineral found chiefly in the zone of oxidation and weathering derived from the alteration of uraninite or other uranium minerals in hypothermal (high temperature) veins.

Common impurities: Ba,Mg

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