Sunday, October 21, 2007

Tiger's eye

Tiger's eye (also Tigers eye, Tiger eye) is a chatoyant gemstone that is generally yellow- to red-brown, with a silky luster. It is a rubbery silicified crocidolite (blue asbestos), a classic model of pseudomorphous replacement. An incompletely silicified blue option is called Hawk's eye. A member of the quartz group, its physical and optical properties are the same or very near to those of single-crystal quartz.

The gems are generally cut en cabochon in order to best display their chatoyancy. Red stones are brought about through calm heat treatment. Honey-coloured stones have been used to try to be like the much higher valued cat's eye chrysoberyl (cymophane), but the overall effect is unconvincing. Artificial fibreoptic glass is a general imitation of tiger's eye, and is produced in a wide range of colours.

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