Tuite

tuite

ringwoodite

majorite

hollandite

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Formula: Ca3(PO4)2
Anhydrous normal phosphate, tuite group, high-pressure mineral
Crystal System: Trigonal
Specific gravity: 3.452 calculated
Streak: White
Colour: Colourless to white
Environments

Meteorites

Localities

At the type locality, the Suizhou meteorite, Xihe, Zengdu District, Suizhou, Hubei, China, tuite was found in a shock melt vein of the chondrite. It occurs as polycrystalline aggregates in association with coarse-grained aggregates of ringwoodite, majorite and NaAlSi3O8-hollandite. These high-pressure mineral assemblages are enclosed in the fine-grained matrix of the vein that consists of majorite-pyrope, FeNi metal and troilite.
The tuite is colourless and transparent with vitreous lustre and a white streak. Tuite in the shock vein of this meteorite was transformed from whitlockite via a shock-produced solid-state reaction, while the pressure and temperature in the shock vein reached 23 GPa and 2000°C (EJM 15.1001-1005).

At the Zagami Martian meteorite, Faskari, Katsina, Nigeria, the high-pressure minerals tuite and ahrensite are located in two small shock-induced melt pockets in the meteorite, coexisting with granular and acicular stishovite and seifertite. Tuite may be formed by decomposition of apatite or by transformation of merrillite under high pressure and temperature conditions. Chlorine-bearing products, presumably derived from the decomposition of apatite, are concentrated along the grain boundaries of tuite grains. Nanocrystalline ahrensite found in a pyroxene clast is likely to be a decomposition product of pigeonite under high pressure and temperature conditions by a solid-state transformation mechanism (AM 107.6.1018–1029).

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