Tiger Eye is a mineral, ranked among precious stones. It is a quartz (SiO2) variety whose color and properties are influenced by the addition of minerals containing iron oxides and hydroxides such as goethite or limonite. Mineral tiger eye is formed as a result of weathering from a similar, but darker, blue-colored mineral falconiho eye. The original mineral is riebeckite from the amphibole group, named after German traveler Emil Riebeck. A "tiger eye" with an appropriate optical effect, imitating the eye of a beast or a predator, is formed by replacing crocidolite (asbestos) fibers with semitransparent chalcedony (quartz) or iron hydroxides in the original mineral. The most famous deposits are found in Africa, India, Myanmar or Australia.