M810 Fluorite

Fluorite, also referred to as fluor-spar, is a mineral composed of Calcium Fluoride.  It is a widely occurring mineral found worldwide and is often found with metallic minerals such as Galena, Sphalerite, Barite, Quartz and Calcite.  Fluorite may fluoresce strongly in ultraviolet light which may be due to the presence of some impurities such as Yttrium.  Blue is the most common color but red, purple, green, yellow and white are also frequent.  It can be used in high performance telescopes, camera lens, enamels and in the making of opalescent glass.