Moskvinite-(Y)
Moskvinite-(Y) is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₂KYSi₆O₁₅.
It crystallizes in the orthorhombic crystal system (space group Ibmm).
Key properties: Mohs hardness 5; specific gravity 2.91; White streak; Vitreous luster; optically biaxial.
IMA symbol Mskv-Y, IMA status: approved, named in 2002.
Found in a boulder of coarse-grained, reedmergnerite-bearing pegmatite in the moraine of the Dara-i-Pioz glacier, Alai mountain ridge, Tien-Shan Mountains, northern Tajikistan.
It is found associated with Shibkovite, nordite-(Ce), leucophanite, microcline, albite, hyalotekite, reedmergnerite, telyushenkoite (Tajikistan); microcline, natrolite, nepheline.
The mineral was named to honor the Russian geologist, A.V. Moskvin (1897-1974), a member of the Pamirs- Tadjikskaya expedition and author of numerous scientific papers on the geology of Central Asia.