Natrosilite is a rare silicate mineral that is colorless or white, transparent to translucent, with pearly luster and is soluble in water. Gems are very rare and mainly for collector’s of the unusual or collectors of water soluble gems. Natrosilite is named for NATRium (sodium), and SILicon in the composition.

The only source for gem quality specimens is the Palitra pegmatite, Kedykverpakhk Mt, Lovozero Massif, Kola Peninsula, Murmanskaja Oblast’, Northern Region, Russia. There is also an occurance of Natrosilite at the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada but the specimens are far too small for gems.

Natrosilite distribution: on Mt. Karnasurt, Lovozero massif, and in the Khibiny massif, Kola Peninsula, Russia. At Mont Saint-Hilaire, Quebec, Canada. 

Chemical Formula: Na2Si2O5
Sodium Silicate
Molecular Weight: 182.15 gm
Composition: Sodium 25.24 % Na 34.03 % Na2O
Silicon 30.84 % Si 65.97 % SiO2
Oxygen 43.92 % O
  100.00 % 100.00 % = TOTAL OXIDE


Crystallography: Monoclinic – Prismatic
Crystal Habit: Thick tabular pseudohexagonal crystals, to 6 cm; granular. 
Twinning: None


Cleavage: Perfect on {100} (micaceous); distinct on {001}; poor on {011}
Fracture: n/a
Tenacity: Brittle
Moh’s Hardness: n. d.
Density: 2.48 (g/cm3)
Luminescence: None
Radioactivity: Not Radioactive
Other: Soluble in water.


Color: Colorless; anomalous blue interference colors in thin section
Transparency: Transparent to translucent
Luster: Pearly
Refractive Index: 1.507 – 1.521  Biaxial ( + )
Birefringence: 0.014
Dispersion: None; r < v
Pleochroism: None