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
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.

Faceted Apatite
Photo courtesty of The Gem Trader

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.