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name:
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Tourmaline Catseye
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| gemstone variety:
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Tourmaline
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| trade name 1:
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Tourmaline Catseye
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| trade name 2:
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| trade name 3:
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| basic colour:
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green
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Colour :
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usually of green colour, but also pink and red colours
are seen as well as any other fancy Tourmaline colour
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Quality :
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important is the sharp eye. The most wanted colours
are a fine emerald-green or a sapphire-blue or a ruby-red.
Catseyes should have no cracks or ugly inclusions.
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History :
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Besides the traditional honey colour
Chrysoberyl-Catseyes, Tourmaline-Catseyes occur in various
beautiful colours. The chatoyancy is caused by thin parallel
crystal tubes.
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Curiosities / Saga :
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Countrys of Origin :
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Brazil and Mozambique
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Birthstone :
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October - Tourmaline
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Hardness :
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7.5
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Treatment :
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sometimes oiled, red Tourmalines may be irradiated
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Size :
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normally from 1.00 to 5.00 carats
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Specific gravity :
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3.10 - 3.26
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Chemical Composition Formula :
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Na(Li,Al,Fe)3 Al6 (BO3)3 Si6O18 (OH)3F
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Chemical Composition Name :
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Hydrous and fluor-bearing sodium- lithium- aluminium-
copper- manganese -boronsilicate
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Crystal system :
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trigonal
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Light refraction :
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1.610 - 1.640
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Double refraction :
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0.016 - 0.022
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