Tiger Eye & Tiger Iron
Both Tiger Eye (which has brown, blue and red varieties) and Tiger Iron are known for their natural shimmering colors--or chatoyancy. In gemology chatoyancy (or chatoyance) is an optical reflectance effect coined from the French chat oeil, meaning cat's eye. Chatoyancy arises either from the fibrous structure of a material, as in Tigers Eye, or from fibrous inclusions or cavities within the stone, like the chrysoberyl inclusions in cat's eye. The effect is similar to the sheen off a spool of silk, or the sun shining on a lovely lake— like a gentle, wavering reflection of color. For a gemstone to show this effect, it is carefully cut with the fibers or fibrous structures parallel to the base of the finished stone. In addition to Western Australia, Tiger Eye stones are found in the Northern Cape Province in South Africa and Thailand, as well as mines in the USA and Canada. What is the difference between Tiger Eye and Tiger Iron?
- Tiger Eye (or Tiger-eye) is available in golden brown, reddish brown, and greenish brown.
- Another variety, called Hawks Eye has a much darker bluish to black color.
- Red Tiger Eye is gently heat treated to bring out the iron oxide that is a natural component of the stone. The blue stones are also heat treated to bring out the blue crocidolite fibers. These beautiful stones are found in the United States, Canada, Korea, China, Brazil, Namibia, India, and Burma.
- Generally, Tiger Iron is a combination of Golden Brown Tiger Eye, Hematite, and Red Jasper. But it is reasonable to think that Tiger Eye stones from Australia, also known for its beautiful hematite, might show distinct hematite banding (or layers). Hematite has a gunmetal gray silky sheen.
- Pietersite is another lovely stone related to Tiger Eye that also features golden browns and yellows, reddish browns, blues, and hematite banding. The chatoyancy in Pietersite is also due to natural fibers in the stones, making the surface appear to shimmer as the stone is rolled from side to side.