Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
Rock Type: mineral

Physical Properties
Hardness: 6.5-7 Mohs; Color: Golden yellow to brown with silky chatoyancy; Luster: Silky/Vitreous; Crystal Structure: Trigonal (fibrous aggregate); Cleavage: None; Specific Gravity: 2.64-2.71
Formation & Geological History
Formed through the pseudomorphism of blue crocidolite (asbestos) into quartz. Iron within the mineral oxidizes to create the golden-brown color. Predominantly found in Precambrian iron formations.
Uses & Applications
Extensively used in lapidary work for cabochons, beads, jewelry, and ornamental carvings. It is also popular in holistic and metaphysical practice.
Geological Facts
The 'eye' effect, known as chatoyancy, is caused by light reflecting off the internal fibrous structure. If the stone is gray-blue, it is called Hawk's Eye; if red, it is often heat-treated and called Bull's Eye.
Field Identification & Locations
Identify by its distinct bands of color that shimmer or 'move' as you rotate the stone under light. Major deposits are found in South Africa, Western Australia, USA, and India.
Identified on: 5/13/2026
Mode: Standard