|
|
name:
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Chrome Tourmaline
|
| gemstone variety:
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Tourmaline
|
| trade name 1:
|
Chrome Tourmaline
|
| trade name 2:
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Chrome Green Tourmaline
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| trade name 3:
|
|
| basic colour:
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green
|
|
|
Colour :
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intense chrome green
|
Quality :
|
the more desirable colour is a vivid emerald-green
colour. The intensity should be an optimum, not a maximum.
Facetted chrome green Tourmalines should have no visible
inclusions and balanced proportions in the cut.
|
History :
|
The name tourmaline is derived from the Singhalese
word "turamali" meaning gemstone. The chrome-green
Tourmalines today are the most attractive and desirable of
green colour Tourmalines.
|
Curiosities / Saga :
|
|
Countrys of Origin :
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Kenya and Tanzania
|
Birthstone :
|
October - Tourmaline
|
Hardness :
|
7.5
|
Treatment :
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none
|
Size :
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normally from 0.50 to 3.00 carats
|
Specific gravity :
|
3.10 - 3.26
|
Chemical Composition Formula :
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Na(Li,Al,Fe,Cr)3 Al6 (BO3)3 Si6O18 (OH)3F
|
Chemical Composition Name :
|
Hydrous and fluor bearing sodium- lithium- aluminium-
iron- chrome boronsilicate
|
Crystal system :
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trigonal
|
Light refraction :
|
1.610 - 1.640
|
Double refraction :
|
0.016 - 0.022
|
|
|
