Hexacelsian

hexacelsian

gurimite

khesinite

zadovite

Images

Formula: Ba(Al2Si2O8)
Tectosilicate (framework silicate), feldspar group, high-temperature paramorph of celsian and paracelsian, barium-bearing mineral
Crystal System: Hexagonal
Specific gravity: 3.305 calculated
Streak: White
Colour: Colourless
Environments

Metamorphic environments

Hexacelsian is a comparatively new mineral, approved in 2015 and to date (October 2023) reported only from the Hatrurim basin (two localities).

Localities

At the type locality, the Gurim anticline, Hatrurim Basin, Tamar Regional Council, Southern District, Israel, two new barium-bearing minerals, gurimite and hexacelsian, were discovered in veins of paralava cutting gehlenite-flamite hornfels. Gurimite and hexacelsian occur in oval polymineralic inclusions in paralava and are associated with gehlenite, pseudowollastonite or wollastonite, rankinite, flamite, larnite, schorlomite, andradite, fluorapatite, fluorellestadite, kalsilite, cuspidine, aradite, zadovite and khesinite. Gurimite and hexacelsian form elongate crystals less than 10 µm thick. The minerals are colourless and transparent with a white streak and vitreous lustre
It is suggested that after relatively fast crystallisation of the main constituents of the paralava, gurimite, hexacelsian and other barium-bearing phases crystallised from residual melt enriched in incompatible elements that filled interstices between crystals of the main constituents (MM 81.4.1009-1019).

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