Pietersite
Last updated: April 2026
Trade name for a brecciated aggregate of hawk's eye (blue crocidolite-replaced quartz) and tiger's eye (iron-oxide-stained quartz), with angular fragments re-cemented by secondary silica. Discovered in Namibia in 1962. The mixture of blue, gold, and red in a brecciated pattern is visually distinctive.
Pietersite has a specific gravity of 2.61 and a refractive index of 1.534–1.540, with a Mohs hardness of 6.5–7.0. It is aggregate.
Physical & Optical Properties
Key Differentiators
- Chaotic angular brecciated pattern — blue, gold, and red-brown zones in broken fragments cemented by later silica
- Blue (hawk's eye), gold (tiger's eye), and red-brown zones all occurring in the same stone
- Chatoyancy visible in individual color zones when cut en cabochon
- Distinguished from tiger's eye (parallel fibrous, single color) and hawk's eye (blue parallel, not brecciated) by angular chaotic fragmentation
- Primary source: Outjo District, Namibia; secondary: Hunan Province, China
Common Simulants
- Tiger's Eye: Tiger's eye has parallel linear fibrous structure (not brecciated/angular), single golden-brown color range, no blue zones, consistent chatoyancy direction throughout.
- Hawk's Eye: Hawk's eye has parallel linear fibrous structure throughout, uniformly blue-gray, no angular breccia pattern, single chatoyancy direction.
- Synthetic Fiber-Optic Cat's Eye Glass: Glass cat's eye: single bright line chatoyancy (not broad zone chatoyancy), RI ~1.50–1.51, SG variable, isotropic, no fibrous mineral texture under magnification, perfect uniform appearance.
Treatments
- Wax or Oil Impregnation (surface stabilization)
- Heat Treatment (alters blue hawk's eye tones to gold/red)
Price Context
Price context is approximate. GemID is not an appraisal tool. Results are indicators, not certified valuations.
Measurement Guides
Identifying a pietersite? GemID walks through these tests in order — RI, SG, fluorescence, and more.
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