Impurities add value to mineral.
Fluorspar is found in granite, it fills cracks and holes in sandstone and it is found in large deposits in limestone.
Pure fluorspar is colourless, but a variety of impurities give fluorite a rainbow of colours, including green, purple, blue, yellow, pink, brown, and black.
Fluorite from Rogerley Mine is dark emerald green with a strong blue-purple daylight fluorescence and an even stronger purple-white fluorescence under longwave ultraviolet light.
Fluorite crystals can be well formed, beautiful and highly prized by collectors.
An average flat crystal, ranging from nine to 13cm in size, from Rogerley Quarry can fetch up to pounds 80 ($150) on the American collectors' market.
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|Publication:||The Journal (Newcastle, England)|
|Date:||Aug 30, 2004|
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