Goryainovite

goryainovite

pyrrhotite

hydroxylapatite

magnetite

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Formula: Ca2(PO4)Cl
Anhydrous phosphate
Specific gravity: 2.98 calculated
Hardness: 4
Streak: White
Colour: Colourless
Luminescence: Goryainovite has a bright orange cathodoluminescence, easy distinguishable from the pale blue cathodoluminescence of co-existing hydroxylapatite. Synthetic Ca2(PO4)Cl fluoresces pale orange under 254 nm UV radiation and does not fluoresce under 385 nm UV (AM 106.161-162).
Environments

Metamorphic environments

Goryainovite was approved in 2016 and to date (June 2022) it has been reported only from the type locality.

Localities

At the type locality, Stora Sahavaara, Sahavaara, Pajala, Norrbotten County, Sweden, iron ore lenses up to 1.3 km long and 80 m thick are situated at the contact greenstone rocks (metamorphosed conglomerate, quartzite, banded iron formation, black schist, dolostone, phyllite, tholeiitic lava and tuff, and dolerite) in the footwall and medium-grade metamorphosed volcanic and sedimentary rocks in the hanging wall. Host diopside-amphibole skarn gradually transforms into a magnetite-serpentine rock with relics of diopside, tremolite, phlogopite and newly formed chlorite, pyrrhotite, pyrite, chalcopyrite and valleriite.
Goryainovite was found in one specimen as small rounded grains up to 20 μm included in anhedral magnetite grains up to 1 mm in serpentine pseudomorphs after diopside with pyrrhotite, chalcopyrite and chlorine-rich hydroxylapatite. The magnetite commonly contains octahedral inclusions up to 10 μm of spinel and, rarely, of anhydrite, thorianite, dolomite and magnesite.
Goryainovite is an early-formed phosphate. When chlorine fugacity (effective partial pressure) decreased, goryainovite was transformed into chlorapatitehydroxylapatite, and only grains isolated in magnetite remained unaltered (AM 106.161-162).

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