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cat's eye




cat's eye
Cat's eye alexandrite
Image: ICA/Bart Curren

Any of several types of gemstone which, when cut to form a convex surface, shows a thin line of light like a cat's eye (chatoyancy). The commonest is chalcedony; the rarest is cymophane, a green variety of chrysoberyl, found in Sri Lanka. The effect is due to minute parallel inclusions or cavities.


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   • GEOLOGY AND PLANETARY SCIENCE