mineral
Tumbled hawk’s eye (blue tiger’s eye)
Quartz (SiO₂) with parallel, crocidolite-derived fibrous inclusions
AI-generated identification · may be incorrectMohs hardness 7; polished, glassy-to-silky luster with blue-gray and brown chatoyant bands. Trigonal quartz; the rounded shape and shine indicate tumbling. Exact identification is uncertain from the image alone.
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Physical properties
Mohs hardness 7; polished, glassy-to-silky luster with blue-gray and brown chatoyant bands. Trigonal quartz; the rounded shape and shine indicate tumbling. Exact identification is uncertain from the image alone.
Formation & geological history
Forms when silica replaces fibrous crocidolite, preserving its aligned structure; iron oxidation can create brown tiger’s-eye bands. The source rocks are commonly Precambrian, though the specimen’s age cannot be determined visually.
Uses & applications
Primarily used for beads, cabochons, carvings, and inexpensive collectible stones.
Geological facts
Its moving, reflective band is chatoyancy, caused by light reflecting from aligned fibers.
Field identification & locations
Look for a smooth, shifting band of light that runs parallel to the fibers; common sources include South Africa, Australia, and India. A definitive distinction from related banded quartz may require closer examination.
