Yegorovite, ([Na<sub>4</sub>[Si<sub>4</sub>O<sub>8</sub>(OH)<sub>4</sub>]÷7H<sub>2</sub>O]) is a silicate mineral found in a hyperalkaline pegmatite in the Lovozero Pluton at Mt. Kedykverpakhk in the Kola Peninsula of Russia. It was named in memory of Russian crystallographer Yurii Kavdievich Yegorov-Tismenko, and approved by the Commission on New Minerals and Mineral Names, International Mineralogical Association in 2008.
Yegorovite is colorless, with a white streak. Found in small quantities among pegmatites. It is a natural silicate of alkali cations.
The chemical composition of yegorovite in elemental weight percent is as follows:
The crystal structure of yegorovite is made up of a single chain of four silicon (Si) tetrahedrons [Si<sub>4</sub>O<sub>8</sub>(OH)<sub>4</sub>]<sup>âÂÂ</sup> and sixfold polyhedrons of [NaO(OH)<sub>2</sub>(H<sub>2</sub>O)<sub>3</sub>] and [NaO(OH)(H<sub>2</sub>O)<sub>4</sub>] centered by sodium (Na).