Difference between revisions of "Apatite"
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{{apatite}} | {{apatite}} | ||
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+ | Apatite is named "the deceiver" as it's color, refractmeter and specific gravity readings are similar to many common gemstones. | ||
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[[Image:Apatite.gif|left|thumb|250px|Faceted Apatite <br />Photo courtesty of The Gem Trader]]<br clear="left" /> | [[Image:Apatite.gif|left|thumb|250px|Faceted Apatite <br />Photo courtesty of The Gem Trader]]<br clear="left" /> | ||
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+ | ==Diagnostics== | ||
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+ | ===Spectoscope=== | ||
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+ | Apatite will, usually, show a rare earth spectrum line in the blue (prasodymium). Blue-green stone will have added spectrum lines in the yellow (didymium) and line(s) in the green (prasodymium). | ||
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+ | ===Chelsea Color Filter=== | ||
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+ | Green-blue stones: green | ||
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+ | ===Dichroscope=== | ||
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+ | Apatite has weak pleochroism, so this tool may not be very useful. | ||
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+ | ===Polariscope=== | ||
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+ | A nice uniaxial negative interference figure should be found. |
Revision as of 09:24, 3 June 2007
Apatite | |
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Chemical composition | Ca5(PO4)3(F,Cl,OH) |
Crystal system | Hexagonal |
Habit | Prismatic |
Cleavage | Imperfect, basal |
Fracture | Conchoidal |
Hardness | 5 |
Optic nature | Uniaxial - |
Refractive index | 1.63-1.64 |
Birefringence | 0.003 |
Dispersion | Low, 0.013 |
Specific gravity | 3.2 |
Lustre | Vitreous |
Pleochroism | Weak |
Apatite is named "the deceiver" as it's color, refractmeter and specific gravity readings are similar to many common gemstones.
Diagnostics
Spectoscope
Apatite will, usually, show a rare earth spectrum line in the blue (prasodymium). Blue-green stone will have added spectrum lines in the yellow (didymium) and line(s) in the green (prasodymium).
Chelsea Color Filter
Green-blue stones: green
Dichroscope
Apatite has weak pleochroism, so this tool may not be very useful.
Polariscope
A nice uniaxial negative interference figure should be found.