It comes in a range of colours.
Fluorite is a beautiful gemstone, but as it is softer than many gems, few jewellers attempt to set it into precious metals. That said, those jewellers that have experience working with Fluorite, find the gem fairly easy to prong set into pendants and earrings.
Interestingly, the most famous location for this amazing gem, a gem that often is bi-coloured, is Castleton in Derbyshire, England. This is where the famous Blue John is found and is highly prized as an ornamental stone. The English miners used to call the crystals ‘ore flowers’ and gem collectors for many years have referred to Fluorite as ‘the most colourful mineral in the world’.
Its name is derived from the Latin word “fluere”, which means “to flow” and refers to the gem’s low melting point. As mentioned under fluorescence, the household fluorescent tube owes the “fluorescent” part of its name to this gemstone.
The reason for this is that many pieces of Fluorite fluoresce when placed under ultraviolet light. Although blue is the most common colour to fluoresce in Fluorite, it is also possible to see red, purple and green glowing within the gem. The colour of the fluorescence varies due to the presence of different impurities and these are often used by gemmologists to identify the gem’s origin.
As well as being discovered in the UK (where it is not normally of gem-quality), Fluorite is also mined in various states in the USA, including Oklahoma, Kentucky, Colorado, Arizona and even New York. Other countries that mine Fluorite include Germany, Switzerland, Mexico and Canada.
Last year I purchased some gorgeous Fluorite rough from Africa. The gem is banded and is therefore known as “Zebra Fluorite”, but rather than the colours being black and white, they are lovely blend of “Rose de France” purple and a teal green. Whilst most lapidarists will only cabochon cut Fluorite due to the gem’s relative softness, our team of highly experienced lapidarists have cut the gemstone into a mixture of ovals and emerald shapes.
Most recently a unique Fluorite was discovered in China. This variety when treated with irradiation and heat turns the gemstone into one of the most stunning colour change gemstones you will ever see. In daylight the gem is a beautiful almost Tanzanite blue, but when seen in incandescent light such as a candle or yellow light bulb, the gem turns a stunning pinkish purple colour. Unlike some colour change gemstones where you have to use a little imagination to see the colour shift, the transformation in Colour Change Fluorite is mesmerising.