Colorless vitreous microcrystals of the extremely rare mineral of simple chemistry ertixiite (Na2Si4O9) from the type and only known locality worldwide in China: Koktokay No. 3 Pegmatite, Altay Mine, Koktokay Pegmatite Field, Aletai Prefecture, Xinjiang Autonomous Region, China (People's Republic). Probably analyzed by the former owner of the specimen (the Vandenbroucke Museum) but the analysis is no longer available. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Ertixiite
Ertixiite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₂Si₄O₉.
It crystallizes in the cubic crystal system.
Key properties: Mohs hardness 5.8–6.5; specific gravity 2.35; White streak; Vitreous luster.
IMA symbol Ert, IMA status: approved, named in 1983.
Occurs as linings of miarolitic cavities in a Ta-Nb-Be-bearing granite pegmatite.
It is found associated with Topaz, albite, muscovite, quartz, apatite, garnet.
The name refers to the Ertixi River, near the occurrence in China.