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Formula: KZr2Li3Si12O30
Cyclosilicate (ring silicate), osumilite group,
lithium-bearing mineral
Crystal System: Hexagonal
Specific gravity: 2.90 measured
Hardness: 7
Colour: Violet, pale pink
Common impurities: Al,Mn,Mg,Ba
Environments
Localities
At the type locality, the Dara-i-Pioz Glacier, Districts of Republican Subordination, Tajikistan, The
sogdianite was found as platy deposits up to 10 X 7 X4 cm in a vein in a
pegmatite of
alkaline-granitic composition, consisting of
microcline, quartz and
aegirine. The central part of the vein, with which sogdianite is
mostly associated, consists essentially of a quartz core with phenocrysts of
microcline, aegirine, and
rare-earth minerals such as thorite and
stillwellite.
Sogdianite occurs either included in quartz, or rarely in interstices
between microcline crystals
(AM 54.1221, ). It occurs as tabular crystals to 1 cm and platy aggregates to 15 cm. Associated minerals include
thorite, stillwellite,
pyrochlore, tienshanite,
thorite, kupletskite-(Cs),
microcline, quartz and
aegirine
(HOM ).
At Washington Pass, Golden Horn Batholith, Okanogan county, Washington, USA, sogdianite occurs in a
pegmatite vein with a composition about that of an alkalic
granite. Associated minerals include
aegirine and polylithionite
(HOM ).
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