Reference work entry
This is gem-grade fluorite that is mainly composed of CaF 2. Fluorite usually contains impurities, where Ca is often replaced by Y and Ce. Fluorite has a rich colour, and the gem-grade stones are usually light green or dark green, blue, bluish green, purple, brown, yellow, pastel, brown, rose red, deep red and colourless. Fluorite sometimes has many colours in one stone. The colour-rich stones can be polished to become gems. Gem-grade fluorite is mainly mined in the United States, Colombia, Canada, Russia, Australia, South Africa and Mexico. China has the highest fluorite production in the world. Fluorite is fluorescent, so glows in the dark (Fig. 11).
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