Cryolite

Name:
Cryolite
Detailed information:

Chemistry name:	Greenland spar; icestone
M Formula:	Na3AlF6
Properties:
Colorless to white, sometimes red, brown, or black; vitreous to greasy luster. Hardness 2.5, d 2.95–3.0. Refr index 1.338, mp 1000 C. Soluble in concentrated sulfuric acid and in fused aluminum and ferric salts.
Occurrence:
Colorado; the former U.S.S.R., Greenland (only commercial source).
Derivation:
Synthetic product is made by fusing NaF and aluminum fluoride.
Use:
Electrolyte in the reduction of alumina to aluminum; ceramics; insecticide; binder for abrasives; electric insulation; explosives; polishes.