Tiger's eye updated

Tiger's eye (also called tiger eye) is a chatoyant gemstone that is usually a metamorphic rock with a golden to red-brown colour and a silky lustre. As members of the quartz group, tiger's eye and the related blue-coloured mineral hawk's eye gain their silky, lustrous appearance from the parallel intergrowth of quartz crystals and altered amphibole fibres that have mostly turned into limonite.

Other forms of tiger's eye

Tiger iron is an altered rock composed chiefly of tiger's eye, red jasper and black hematite. The undulating, contrasting bands of colour and lustre make for an attractive motif and it is mainly used for jewellery-making and ornamentation. Tiger iron is a popular ornamental material used in a variety of applications, from beads to knife hilts.

Tiger iron is mined primarily in South Africa and Western Australia. Tiger's eye is composed chiefly of silicon dioxide (SiO
2) and is coloured mainly by iron oxide. The specific gravity ranges from 2.64 to 2.71. It is formed by the alteration of crocidolite.

Serpentine deposits in the US states of Arizona and California can have chatoyant bands of chrysotile, a form of asbestos, fibres. These have been cut and sold as "Arizona tiger-eye" and "California tiger's eye" gemstones.[4][5] The trade name 'pietersite' is used for a fractured or brecciated chalcedony containing amphibole fibers and promoted as tiger's eye from Namibia and China