Fluorite is a calcium fluoride crystal with a hardness of 4. Its growth pattern is cubic or octahedral, and it occurs in hydrothermal veins, often in association with minerals such as Quartz, Calcite and Barite. It can be found in a wide range of colours, including colourless, green, purple, white, yellow, red, pink and black. Fluorite has lent its name to the property of fluorescence, the display of vivid glowing colours under ultraviolet light. Important Fluorite deposits have been found in Germany, England, China, Argentina and the USA.