is a white or colorless mineral form of sodium
aluminofluoride, which crystallizes in the monoclinic
system but has a pseudocubic aspect; found in
masses of waxy luster; hardness is 2.5 on Mohs
scale, and specific gravity is 3.0. The powder
becomes almost invisible in water due to its
low refractive index. It is mined in significant
quantities in Greenland ( so also known as Greenland
spar; ice stone), and in small amounts in elsewhere.
Synthetic cryolite is manufactured from hydrofluoric
acid, sodium carbonate, and aluminium. Synthetic
cryolite is used chiefly as a flux in the electrolytic
production of aluminum from bauxite as
it effectively lowers down the melting point
of alumina. It is used in the glass and enamel
industries, in bonded abrasives as a filler,
in making salts of sodium and aluminum and porcelaneous
glass and in the manufacture of insecticides.
Cryolite is a relatively safe fruit and vegetable
insecticide. The fluoride ion
inhibits many enzymes that contain iron, calcium, and magnesium. Several of
these enzymes are involved in energy production in cells, as in the case of
phosphatases and phosphorylases.