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Formula: NaMgAl3(PO4)2(OH)6.8H2O
Hydrated phosphate
Crystal System: Trigonal
Specific gravity: 2.22 calculated
Streak: White
Colour: Colourless
Common impurities: F
Environments
Sedimentary environments
Hydrothermal environments
Tomsquarryite is a new mineral, approved in 2022 and to date (August 2023) reported only from the type locality.
Localities
There are two co-type localities, the Penrice marble quarry, Penrice, Barossa Valley, and Tom's Quarry, Kapunda, both
at the North Mt Lofty Ranges, South Australia, Australia. They are both
phosphorite deposits. The formation of tomsquarryite at the
Penrice quarry is related to the alteration of minyulite, in a near-neutral
solution. At Tom's quarry, formation is thought to involve progressive surface alteration of
gordonite, most likely by a dissolution/reprecipitation mechanism in a
sodium- and fluorine- bearing solution.
Thin layers of tomsquarryite and other intimately mixed fine-grained
secondary phosphates coat a
goethite-clay matrix (Tom's quarry) and a
goethite, manganese oxide,
muscovite matrix (Penrice quarry).
Tomsquarryite crystals are talc-like platelets with diameters of a few
tens of micrometres and thicknesses of only ∼ 1 µm (Penrice quarry) and thicker (∼ 10 µm) flattened pseudohexagonal
crystals (Tom's quarry).
At both locations, tomsquarryite was found in association with
angastonite, penriceite,
elliottite, minyulite,
goethite and wavellite
(AM 108.1571, Mindat).
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