Difference between revisions of "Fluorite"
From The Gemology Project
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One can see this when a small amount of fluorite is placed on a teaspoon and heated over a candle for a few minutes (in a dark room).<br /> | One can see this when a small amount of fluorite is placed on a teaspoon and heated over a candle for a few minutes (in a dark room).<br /> | ||
Material from Telemark, Norway will show a blue-green thermoluminescence. | Material from Telemark, Norway will show a blue-green thermoluminescence. | ||
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+ | ===Optical phenomena== | ||
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+ | ====Color change==== | ||
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+ | Color change fluorite has been reported with a change from blue to purple (much like some color change garnet). |
Revision as of 04:59, 20 September 2008
Fluorite | |
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Chemical composition | CaF2
Calcium fluoride |
Crystal system | Cubic |
Habit | Octahedral, cubes, interpenetrant twins |
Cleavage | Perfect, octahedral |
Fracture | Conchoidal |
Hardness | 4 |
Optic nature | Isotropic |
Refractive index | 1.434 |
Birefringence | Isotropic |
Dispersion | Very low, 0.007 |
Specific gravity | 3.18 |
Lustre | Poor vitreous |
Fluorescence | Bluish-white, purple (LW) |
Diagnostics
Thermoluminescence
FLuorite may luminesce when heated. The stored energy from UV radiation is released if heated to a certain temperature and the effect depends on the amount of stored energy.
One can see this when a small amount of fluorite is placed on a teaspoon and heated over a candle for a few minutes (in a dark room).
Material from Telemark, Norway will show a blue-green thermoluminescence.
=Optical phenomena
Color change
Color change fluorite has been reported with a change from blue to purple (much like some color change garnet).