Formula: Ca4(Mg2Fe3+10)O4(Fe3+10Si2)O36
Inosilicate (chain silicate), sapphirine supergroup
Crystal System: Triclinic
Specific gravity: 4.097 calculated
Hardness: 6
Colour: Black to dark brown
Luminescence: No fluorescence under UV

Metamorphic environments


At the type locality, the Gurim anticline, Hatrurim Basin, Tamar Regional Council, Southern District, Israel, khesinite was discovered in thin veins of paralavas within fine-grained gehlenite rocks. Paralavas are composed of rankinite, pseudowollastonite, rarely wollastonite, flamite, kalsilite, cuspidine, schorlomiteandradite, gehleniteåkermanite, magnesioferrite-–spinel and fluorapatitefluorellestadite. Accessory and rare minerals are represented by baryte, walstromite, fresnoite, vorlanite, barioferrite, hematite, perovskite, gurimite, zadovite, aradite and hexacelsian.
Khesinite crystallised in paralava from melt, sometimes forming isolated crystals, but more commonly reaction rims on magnesioferrite in association with pseudowollastonite and flamite at temperature not lower than 1200°C (EJM 29.1.101–116).

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