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Formula: CaMgAl(PO4)2(OH).4H2O
Hydrated phosphate with hydroxyl, overite group
Crystal System: Orthorhombic
Specific gravity: 2.53 measured, 2.51 calculated
Hardness: 3½ to 4
Streak: White
Colour: Light apple-green to colourless; colourless in transmitted light
Solubility: Readily soluble in hot nitric acid
Environments:
Pegmatites
Hydrothermal environments
Overite is a secondary phosphate mineral found in altered
phosphate nodules in sediments and in granitic
pegmatites
(Dana).
Localities
At the Tanco Mine, Bernic Lake, Lac-du-Bonnet area, Manitoba, Canada, overite occurs in a complex
granite pegmatite
(HOM).
The assemblages of minerals in the pegmatite were deposited in
succession from petalite + quartz to
spodumene + quartz to
eucryptite + quartz
(R&M 92.2.153).
At the type locality, Clay Canyon, Fairfield, Oquirrh Mountains, Utah county, Utah, USA, overite is associated with
crandallite, variscite and
apatite
(Dana, HOM).
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