Sogdianite

sogdianite

thorite

stillwellite

tienshanite

Images

Formula: KZr2Li3Si12O30
Cyclosilicate (ring silicate), osumilite group, lithium-bearing mineral
Specific gravity: 2.90
Hardness: 7
Colour: Violet, pale pink
Common impurities: Al,Mn,Mg,Ba
Environments

Pegmatites

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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