Zeravshanite

Formula: Cs₄Na₂Zr₃[Si₁₈O₄₅](H₂O)₂

Origin of name: for the type locality, Verkhnii Dara-i-Pioz massif, at the joint of the Zeravshan, Turkestan and Alay ranges, Tajikistan

Crystal system: Monoclinic

Crystal class: 2/m

Twinning: 

Unit cell: a = 26.3511 Å, b = 7.5464 Å, c = 22.9769 Å, β = 107.237°

Colour: Colourless

Diaphaneity: Transparent

Luster: Vitreous

Habit: Irregular grains and intergrowths of tabular crystals to 0.2 mm

Hardness: 6

Specific gravity: 3.18 (calculated), 3.09 (measured)

Cleavage: in one unspecified direction

Tenacity: Presumably brittle

Streak: White

Synonyms/varieties:

Comments:  IMA approved 2003. Found in rocks from the glacial moraine. Associated minerals are: quartz, aegirine, polylithionite, reedmergnerite, pectolite, sogdianite, leucosphenite, stillwellite-(Ce), microcline, baratovite, fluorite, galena, turkestanite, eudialyte group minerals, neptunite, pekovite and other accessory minerals.