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Formula: BaB2Si2O8
Tectosilicate (framework silicate), barium- and
boron- bearing mineral
Crystal system: Orthorhombic
Specific gravity: 3.78 measured, 3.79 calculated
Hardness: 7
Streak: White
Colour: White
Luminescence: Bright blue fluorescence under short wave UV
Environments
Maleevite was approved in 2002 but to date (April 2025) it has been reported only from the type locality.
Localities
At the type locality, the Dara-i-Pioz Massif, Districts of Republican Subordination, Tajikistan, the Dara-i-Pioz
glacier descends from the southern slope of the Igla Mountain, which is situated at the intersection of the Turkestan,
Alai and Zeravshan mountain ranges. Fragments of alkaline rocks and
pegmatites of the upper Dara-i-Pioz massif occur in the
moraine of the glacier. The massif is known for very high contents of boron,
and hence the widespread and varied occurrence of boron minerals, including
tienshanite,
tadzhikite-(Ce),
kapitsaite-(Y),
maleevite and pekovite, that were first described from this massif.
Maleevite was found in a single slightly rounded block of
pegmatite in
syenite, 1 x 0.8 x 0.7 m3 in size. This
pegmatite is a medium- to coarse- grained rock that
consists mainly of quartz,
microcline and aegirine, with
subordinate arfvedsonite,
polylithionite,
reedmergnerite,
kupletskite-(Cs),
hyalotekite, albite,
dusmatovite, pyrochlore,
tadzhikite-(Ce), tienshanite,
sogdianite,
stillwellite-(Ce),
leucosphenite,
leucophanite, willemite,
danburite, zektzerite,
berezanskite, baotite,
cappelenite-(Y) and an unknown Y–Ca silicate.
Maleevite occurs as anhedral equant crystals from 0.5 to 2 mm across, and rarely as tabular grains in
quartz
(CM 42.1.107-119).
Maleevite from the Dara-i-Pioz Massif -
Image
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