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Fluorite en.wikipedia.org Fluorite (also called fluor-spar) is a mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon. Crystal twinning is common and adds complexity to the observed crystal habits.s.... Fluorite gives its name to the property of fluorescence, as many samples fluoresce strongly in ultra-violet light. The fluorescence may be due to impurities such as yttrium or organic matter in the crystal lattice. Fluorite's fluorescence color is largely dependent on where the original specimen was located. Blue is the most common color but red, purple, yellow, green and white also occur. Fluorite also exhibits the property of thermoluminescence.... www.galleries.com The many colors of fluorite are truly wonderful. The rich purple color is by far fluorite's most famous and popular color. It easily competes with the beautiful purple of amethyst. Often specimens of fluorite and amethyst with similar shades of purple are used in mineral identification classes to illustrate the folly of using color as the sole means to identify minerals. The blue, green and yellow varieties of fluorite are also deeply colored, popular and attractive. The colorless variety is not as well received as the colored varieties, but their rarity still makes them sought after by collectors. A brown variety found in Ohio and elsewhere has a distinctive iridescence that improves an otherwise poor color for fluorite. The rarer colors of pink, reddish orange (rose) and even black are usually very attractive and in demand. www.geology.about.c.com Mineral collectors prize fluorite for its very wide range of colors, but it's best known for purple. It also often shows different fluorescent colors under ultraviolet light. And some fluorite specimens display thermoluminescence, emitting light as they are heated. No other mineral displays so many kinds of visual interest. Fluorite also occurs in several different crystal forms. ..... |
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