Tiger's Eye

WHAT IS IT?

  • A Quartz (SiO2) based metamorphic gemstone containing hydrous Iron Oxide Goethite (Fe0Oh)

  • Has an optical reflectance known as Chatoyancy (French for “Cat’s eye”) giving it a silky luster

  • The color varies from golden to red-brown

  • Formed when fibrous Crocidolite (Blue Asbestos) is fully replaced by silica. The Quartz dissolves the Crocidolite leaving the Quartz in a fibrous form. Process is known as pseudomorphosis.

  • Note: currently, there is a debate on how Tiger's Eye forms. An alternate theory has been proposed by Hearney & Fisher (2003).

  • Mohs Scale Hardness: varies from 5.5 to 7.0 (may contain layers hardness)

  • Specific Gravity: 2.64—271

  • Streaks are usually blue-gray, gold-brown, or yellow

  • Tiger Iron is composed of Tiger's Eye, Red Jasper, and Black Hematite.

  • Marra Mamba is a rare and expensive form of Tiger Iron containing red, yellow, and blue bands that is only found near Mount Brockman in Australia

  • Hawk's Eye Quartz is a blue colored relative that contains some Blue Asbestos

  • Serpentine containing Chatoyant bands of Chrysotile (white asbestos) fibers is found in Arizona & California. These are known as "Arizona Tiger's Eye' and "California Tiger's Eye" respectively. They are Serpentines,  are not true Tiger's Eye

  • Not as valuable as Cat's Eye Chrysoberyl ( aluminate of beryllium). Cat'sEye is more translucent and brighter and occurs in a greater variety of colors (green, yellow, brown, and sometimes blue). Cat's Eye contains embedded Asbestos (magnesium containing fibrous silicate) and Actinolite (inosilicate) fibers.

  • Imitation/counterfeit Tiger's eye is common

  • Dark Tiger's Eye stones are lightened using nitric acid, oxalic acid, or hydrochloric acid

  • Red Tiger’s Eye can be produced by heating (also used for counterfeiting)

  • Because Tiger 's Eye is often layered with materials of various hardness(as in Tiger Iron), it can often be difficult to polish without under-cutting

  • Tiger's Eye must be cut parallel to the fibers. A 90 degree cut results in a loss of Chatoyance

  • There are a number other related minerals (Piertersite, Binghamite, Silkstone)

WHERE IS IT FOUND?

  • The primary source for Tiger's Eye & Hawks Eye is South Africa (Asbestos Mountains near Griquatown)

  • Other significant sources of Tiger's Eye include Australia, Brazil, Burma, Canada, China, India,Korea, Namibia, Spain, and the USA

  • Tiger Iron is primarily mined in South Africa & Western Australia

  • Cat's Eye is found in India & Sri Lanka

WHAT IS IT USED FOR

  • Used for jewelry. Usually cut into cabochons or beads to emphasize the Chatoyancy

  • In ancient times it was used medicinally and was considered mystical. It is still used in witchcraft.