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Formula: CsNa6Be2Al3Si15O39F2
Phyllosilicate (sheet silicate), leifite group,
cesium- and beryllium-
bearing mineral
Crystal System: Trigonal
Specific gravity: 2.73 measured, 2.73 calculated
Hardness: 6
White
Colour: Colourless to white
Luminescence: Very dim dark purple fluorescence under short wave UV
Common impurities: Zn
Environments
Telyushenkoite was approved in 2001 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, telyushenkoite
was discovered in reedmergnerite boulders found on the moraine of the
Dara-i-Pioz glacier. The massif is located in the upper part of the Dara-i-Pioz valley, at the junction of the
Zeravshan, Alay and Gissar Ranges of the South Tien Shan Mountains.
Telyushenkoite occurs in a rock consisting of 85% to 90% of coarse-grained
reedmergnerite, in which the
reedmergnerite grains reach up to 15 cm across. Euhedral grains of
microcline, up to 5 cm across, and their aggregates constitute ~10% of
the rock; pectolite,
hyalotekite, kentbrooksite,
polylithionite and albite
make up the remaining 5% of the rock. Telyushenkoite occurs as equant grains up to 2 cm across within veinlets
cutting reedmergnerite and
microcline, in close association with
hyalotekite, shibkovite,
nordite-(Ce) and
leucophanite. It also occurs in interstices between grains of
reedmergnerite
(New Data on Minerals, 38. Moscow. 5-8).
Telyushenkoite from the Dara-i-Pioz Massif -
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