Tiger's Eye
Image: James St. John (CC BY 2.0)
Mineral NameTiger's Eye
Chemical FormulaSiO2
Mohs Hardness7
Crystal Systemtrigonal
Lustersilky
Streak Colorwhite
Cleavagenone
Fractureconchoidal
Specific Gravity2.64
Colorsgolden-brown, yellow-brown, reddish-brown
Transparencytranslucent
Type LocalitySouth Africa
Mineral GroupSilicates
Usesjewelry, ornamental objects, carvings
Associated Mineralscrocidolite
Raritycommon
Description
A fibrous, chatoyant variety of quartz, typically golden to reddish-brown, exhibiting a shimmering band of light that moves across its surface. The image shows a rough, golden-brown specimen with a distinct silky luster.
Geological Context
Tiger's Eye forms as a pseudomorph of quartz after crocidolite, a fibrous amphibole mineral. The quartz replaces the crocidolite while preserving its original fibrous structure, which is responsible for its characteristic chatoyancy.
