Yegorovite, ([Na4[Si4O8(OH)4]·7H2O]) 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.[1]

Yegorovite
General
CategorySilicate mineral
Formula
(repeating unit)
Na4[Si4O8(OH)4]·7H2O
IMA symbolYeg
Strunz classification09.DX.00
Dana classification65.01.09.01
Crystal systemMonoclinic
Crystal classPrismatic
H–M symbol: (2/m)
Space groupP22/c
Unit cella = 9.866(7) Å, b = 12.385(5) Å, c = 14.921(1) Å, β = 104.79(6)°, V = 1762(3)ų
Identification
Colorcolorless
TwinningPolysynthetic
Cleavageperfect on {(010) and (001)}
Fracturesplintery
Mohs scale hardness2
LusterVitreous
Streakwhite
DiaphaneityOpaque
Specific gravity1.90
Density1.90(2) g/cm³
Optical propertiesbiaxial (−)
Birefringenceδ = 0.008
References[1][2]

Physical properties

edit

Yegorovite is colorless, with a white streak. Found in small quantities among pegmatites. It is a natural silicate of alkali cations.[1][2]

Chemical composition

edit

The chemical composition of yegorovite in elemental weight percent is as follows:

element weight %
Na2O 23.28
SiO2 45.45
H2O 31.27
Total 100.0

Crystal structure

edit

The crystal structure of yegorovite is made up of a single chain of four silicon (Si) tetrahedrons [Si4O8(OH)4] and sixfold polyhedrons of [NaO(OH)2(H2O)3] and [NaO(OH)(H2O)4] centered by sodium (Na).

References

edit
  1. ^ a b c Pekov, I. V. et al., 2010, Yegorovite, Na4[Si4O8(OH)4]·7H2O, a New Mineral from the Lovozero Alkaline Pluton, Kola Peninsula. Geology of Ore Deposits 52.7 (2010): 584–590.
  2. ^ a b https://www.mindat.org/min-38851.html