Fluorspar

Written by Administrator

Tuesday, 13 November 2007

Fluorspar This mineral is calcium fluoride with the chemical composition CaF2. It occurs in nature in violet, blue, purple, green, yellow, brown, and pink cubic crystals. The best known gem form is the purple-and-white banded variety known as "Blue John," which was much in demand for carved objects and vases. Its only source used to be in Derbyshire, England, before supplies became exhausted. Fluorspar also has many industrial uses. The transparent mineral is used in making lenses, and other pure forms find uses in the manufacture of opalescent glasses and hydrofluoric acid. It has a hardness of only 4, too soft to retain a high polish, and thus is unsuitable as a ring stone.

Last Updated ( Tuesday, 13 November 2007 )