Luobusaite

luobusaite

gupeiite

xifengite

suessite

Images

Formula: Fe_0.84Si₂
Silicide of iron
Crystal system: Orthorhombic
Specific gravity: 4.55 calculated
Colour: Steel-grey
Luminescence: Not fluorescent under UV
Environments

Derived from the mantle

Localities

At the type locality, the Luobusha ophiolite, Qusum County, Shannan Prefecture, Tibet, China, a group of mantle minerals including about 70 to 80 subtypes of minerals has been discovered from a podiform chromitite. Recovered minerals include diamond, coesite, moissanite, wustite, Fe-silicides and luobusaite. All of these minerals were hand-picked from heavy-mineral separates of the podiform chromitite in the mantle peridotite of an ophiolite. The grains of luobusaite are host minerals with inclusions of native silicon or as an intergrowth with native silicon and an Fe-Si phase. Luobusaite occurs as irregular grains, 0.1 to 0.2 mm in size, consisting of very fine-grained aggregates. The mineral is steel-grey in colour, opaque and with a metallic lustre (Acta Geologica Sinica - English Edition, 80.5.656-659).
Luobusaite is part of an Fe-Si phase series including minerals such as gupeiite, xifengite, suessite, hapkeite, naquite and linzhiite. It has a similar X-ray diffraction pattern to that of synthetic orthorhombic FeSi₂ (AM 92.8.1540-1541).

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