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www.mineralgallery.co.za Minerals P-T |
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Tiger's Eye |
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Name
Tiger's eye
Chemistry
SiO2
Uses
As an ornamental stone and to cut jewelery from.
Color
Golden yellow to green to blue.
Hardness
7
Specific gravity
2.7-2.9
Tiger's-eye, a variety of rich golden yellow to brownish quartz, is polished as a semiprecious ornamental stone to display its characteristic band of pearly luminescence resulting from reflection of light from parallel inclusions, called chatoyancy.
The quartz originally contained fibers of crocidolite, a bluish asbestos; their alteration to iron oxides produced color banding. Silica subsequently replaced the iron oxides. In the similar blue-colored gem hawk's-eye, the crocidolite fibers were replaced by silica before alteration.
The best examples have been found at Griqualand West in South Africa.