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.
Physical & Optical Properties
RI Range1.534–1.540
SG Range2.58–2.64
SG Typical2.61
Hardness (Mohs)6.5–7
Crystal SystemAggregate
Optic CharacterAggregate
Dispersion0.000
Fluorescence LWInert
Fluorescence SWInert
Chelsea FilterInert
PleochroismNone
ColorsMulti, Blue Violet, Brown, Yellow Orange
SpeciesPietersite (brecciated hawk's eye and tiger's eye — crocidolite/quartz aggregate)
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
Natural — low ($/ct)$5
Natural — high ($/ct)$40
NotePer carat; commercial ornamental material $5–20/ct; fine Namibian pietersite with vivid blue and complete color range $20–40/ct; larger well-patterned cabochons command premiums
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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