Tiger's Eye (commonly referred to as Blue/Gold Tiger's Eye)

Hardness: 6.5-7 on the Mohs scale. Color: Golden brown, yellowish-brown, sometimes with blue-gray bands (Hawk's Eye). Luster: Silky to vitreous. Crystal structure: Cryptocrystalline (microscopic quartz fibers). It does not have cleavage, rather it shows a conchoidal fracture. Specific Gravity: 2.64-2.71. Known for its chatoyancy, a shimmering, movable optical effect resembling a cat's eye, caused by the fibrous structure.

Tiger's Eye forms when quartz replaces crocidolite (a type of asbestos), retaining the fibrous structure of the original mineral. The golden-brown color is due to the presence of limonite, an iron oxide that stains the quartz fibers during formation. The blue variety (Hawk's Eye) forms when the crocidolite has not fully oxidized to limonite, retaining its original blue-gray color. It typically forms in hydrothermal veins within metamorphic rocks. Geological Age: Varies depending on location, but often found in ancient Precambrian formations.

Primarily used as an ornamental stone and in jewelry for beads, cabochons, carvings, and polished display pieces due to its attractive chatoyant effect. It's also popular in lapidary arts. Less commonly used in construction, but large polished slabs can be used for decorative applications.

Tiger's Eye is believed by some to be a stone of protection and good luck, often associated with courage and confidence. It is a pseudomorph of quartz after crocidolite. The 'eye' effect moves as the stone is tilted, creating a striking visual appeal. Varieties include red Tiger's Eye (heating golden Tiger's Eye) and blue Tiger's Eye (Hawk's Eye).

In the field, it's identified by its characteristic silky luster and chatoyancy, especially when polished, and its fibrous appearance. The golden-yellow to brown coloring with shimmering bands is distinctive. Commonly found in South Africa (especially the Northern Cape Province), Australia, India, Thailand, Myanmar, Brazil, China, and the United States (e.g., Arizona, California). Collectors seek specimens with strong chatoyancy and distinct color banding. It is often cut en cabochon to best display its optical properties.