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Formula: Nb(BO4)
Valence: Nb5+BO4
Monoborate of niobium, forms a series
with béhierite
Crystal System: Tetragonal
Specific gravity: 6.548 calculated
Hardness: 8
Streak: White
Colour: Pink, greyish
Luminescence: Not fluoresecent either under short wave or long wave UV
Environments
Localities
At the type locality, the Antsongombato gem mine, Antsentsindrano, Anosiarivo Manapa, Betafo District, Vakinankaratra,
Madagascar, schiavinatoite occurs in a highly evolved boron-rich
lithium - cesium -
tantalum (LCT) granitic
pegmatite. Associated minerals (in addition to
the normal rock-forming minerals of granitic
pegmatites) include
béhierite, londonite -
rhodizite series minerals,
spodumene, elbaite –
liddicoatite series minerals,
danburite, morganite,
pollucite, manganese-bearing
fluorapatite, uranium-bearing
microlite, xenotime,
monazite, columbite-(Mn),
tantalite-(Mn), hübnerite
and hafnium-bearing zircon.
Schiavinatoite occurs intimately associated with béhierite.
Schiavinatoite was found as part of a well-formed, flattened bipyramidal crystal of
niobium-rich béhierite about 4 mm
across. It is
greyish pink with a white streak and not fluorescent
(CM 39.5.1473-1502, Mindat).
Schiavinatoite from the Antsongombato gem mine -
Image
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