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Formula: NaMgAl3(PO4)2F6.9H2O
Phosphate, paramorph of
penriceite
Crystal System: Monoclinic
Specific gravity: 2.09 calculated
Colour: Colourless
Environments
Sedimentary environments
Hydrothermal environments
Localities
At the type locality, the Penrice marble quarry, Penrice, Barossa Valley, North Mt Lofty Ranges, South Australia,
elliottite is the dominant mineral in an angastonite-type specimen,
associated with crandallite,
minyulite, penriceite,
perhamite and quartz
(AJM 23.1.13-20)>
At Tom's Quarry, Kapunda, North Mt Lofty Ranges, Mt Lofty Ranges, South Australia (about 15 km northwest of Penrice),
phosphorite-type rock is distributed throughout calcareous
clay derived from the decomposition of argillaceous rocks underlying a
marble formation. A specimen was found, 2 cm x 1 cm in size, comprising
hemispherical aggregates, to 1 mm across, of platy crystals of elliottite overgrowing
minyulite on a matrix of goethite.
Penriceite and wavellite are
other closely associated minerals.
Elliottite is formed by the alteration of minyulite in near-neutral
solution, forming amorphous angastonite which subsequently crystallises as
elliottite and penriceite.
The elliottite occurs as colourless, ultra-thin pseudohexagonal platelets, typically 50 to 100 microns across
(AJM 23.1.13-20)>
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