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Formula: Na2(UO2)2(AsO4)2.5H2O
Hydrated arsenate, uranyl mineral,
meta-autunite group, forms
pseudomorphs after
metazeunerite (Dana)
Crystal System: Tetragonal
Specific gravity: 3.846 measured, 3.66 calculated
Hardness: 2½
Streak: Pale yellow
Colour: Lemon-yellow, straw-yellow, yellow-green
Luminescence: Fluoresces bright yellow green in SW and LW
Solubility: Natrouranospinite dissolves readily in dilute acids or in Na2CO3 solution
(AM 43.383-384)
Common impurities: Ca
RADIOACTIVE
Environments
Localities
At the type locality, the Bota-Burum U deposit, Alakol, Almaty Region, Kazakhstan, Natrouranospinite occurs in
fine, tabular to elongated crystals with lengths up to 2 cm, as radial fibrous aggregates, and as square crystals
pseudomorphous after metazeunerite,
sometimes with a core of metazeunerite. The natrouranospinite
occurs in the oxidation zone of a primary hydrothermal uranium-sulphide
deposit containing pitchblende,
arsenopyrite, pyrite and
galena in carbonatised
granitic porphyry and
tuffaceous breccia. Oxidation
caused the formation of realgar, orpiment,
scorodite, mansfieldite,
metazeunerite, trögerite and
arseniosiderite. Natrouranospinite is the most abundant
secondary uranium mineral; it is sometimes replaced by
uranophane
(AM 43.383-384, as sodium uranospinite).
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