Fluorite

About Fluorite

Named because it was used as a flux in smelting (Latin fluere, to flow). The term fluorescence was coined from fluorite - it was the first mineral in which the phenomenon was observed. It can fluoresce in virtually every color under UV light. Blue John is a banded blue-purple variety from England, used in decorative objects for 2,000 years. It is too soft for most jewelry but popular with collectors. China is the largest producer. Crystals can be enormous - specimens over 2 meters have been found. It occurs on every continent. It is thermoluminescent - it glows when heated.