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Formula: Ca2Fe(PO4)2.2H2O
Hydrated normal phosphate, paramorph of
messelite
Crystal System: Triclinic
Specific gravity: 3.14 measured, 3.15 calculated
Hardness: 3½ to 4
Streak: White
Colour: Colorless to pale yellow in transmitted light
Solubility: Insoluble in water or in hydrochloric acid
Environments
Sedimentary environments
Hydrothermal environments
Dondoellite is a new mineral, approved in 2021 and to date (October 2022) reported only from the type locality.
Localities
At the type locality, Grizzly Bear Creek, Stoneman Camp, Rapid Creek, Dawson mining district, Yukon, Canada,
dondoellite was found associated with hydroxylapatite,
siderite and quartz. The host rock
is a sedimentary iron formation with marine phosphorites and
shales.
Dondoellite and associated minerals are found as fracture fillings in the
quartz-phosphate veins.
Evidence suggests that the formation temperature of the quartz-phosphate
veins must have been at least 180–200oC. As for dondoellite, its formation temperature was
estimated to range from 50oC to 200oC, the lowest among all the fracture-filling phosphates.
Dondoellite occurs as
spherical aggregates up to 2 cm across of radiating bladed white to straw-yellow or tan crystals, on top of
orange-brown siderite and white
hydroxylapatite. Individual crystals of dondoellite are up to
0.8 mm in size
(CM 60.837-847).
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