Fluorite
Description
Fluorite – also called fluorspar – is a mineral composed of calcium fluoride. It has a relatively low melting point and was valued as a flux in smelting metals – hence the derivation of its name from the Latin root fluo, meaning ‘to flow’. Fluorite also gave its name to the phenomenon of fluorescence, which is prominent in fluorites from certain locations due to impurities in the crystal, while some fluorite crystals also exhibit phosphorescence. In addition to these rather exotic properties it typically comes in a wide range of colors and has been called ‘the most colorful mineral in the world’. Typical colours – as in this specimen – are rainbow-like purples, blues and greens: these, as in many minerals, are the result of impurities and sometimes, in the case of fluorite, of exposure to radiation.