a fluoride of sodium and aluminum, NaAlF, found in Greenland or produced synthetically and used in the molten state in the electrolytic production of aluminum
See cryolite in American Heritage Dictionary 4
cry·o·lite
noun
An uncommon, white, vitreous natural fluoride of aluminum and sodium, Na3AlF6, nearly invisible in water in powdered form and used chiefly in the electrolytic recovery of aluminum. Also called Greenland spar.