Catseye

Catseye, a variety of quartz containing fibres of some asbestiform mineral, so that when cut en cabochon, i.e. with a rounded or oval surface, it exhibits a moving beam of internally reflected light, as does a cat's eye, whence this property is called chatoyance. Catseyes are generally grey or bluish, and form gems of some value: but the African catseye occurs abundantly in the Asoestos mountains of Griqualand. It is quartz penetrated by fibres of crocidolite, a, greenish asbestos, which is often altered into limonite or hydrous iron oxide so as to produce a beautiful golden-brown catseye. This has of late been largely imported, and unfortunately artificially coloured. It is largely used for the handles of parasols and canes.