Cat's-eye

Cat's-eye, a beautiful variety of chalcedonic quartz receiving its name from the resemblance which the reflection of light from it, especially when cut en cabochon, or in a convex form, is supposed to exhibit to the light that seems to emanate from the interior of the eye of a cat. It has a sort of pearly appearance, and is chatoyant, or characterised by a fine play of light, which is supposed to result from the parallel arrangement of fine fibres of some foreign substance, such as ami- anthus, or of minute hollow tubules similarly arranged. It is of various colours, and is obtained chiefly from India and Ceylon, but occurs also in the Harz. A chatoyant variety of felspar has been sometimes confounded with cat's-eye.