metamorphic
Polished pietersite cabochon
Pietersite (brecciated fibrous quartz/chalcedony, commonly with riebeckite or crocidolite remnants)
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; brown, orange, gray, and blue chatoyant patches with vitreous to waxy luster. Microcrystalline quartz has no visible cleavage and commonly shows tiger’s-eye-like chatoyancy; this specimen is polished and labeled.
Identified More metamorphic →
Explore Polished pietersite cabochon in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness about 6.5–7 Mohs; brown, orange, gray, and blue chatoyant patches with vitreous to waxy luster. Microcrystalline quartz has no visible cleavage and commonly shows tiger’s-eye-like chatoyancy; this specimen is polished and labeled.
Formation & geological history
Forms when fibrous quartz-rich material is brecciated and recemented by silica, preserving aligned amphibole fibers that create chatoyancy. Commercial material mainly comes from Namibia and China, generally formed in Precambrian host rocks.
Uses & applications
Used for cabochons, pendants, beads, and collectible lapidary pieces; it is not a major construction or industrial stone.
Geological facts
Its strongest identifying feature is shifting, silky reflection as the stone moves under light. Pietersite is sometimes marketed as “tempest stone” and may be confused with tiger’s eye or hawk’s eye.
Field identification & locations
Look for irregular breccia-like brown-gold or blue-gray color zones and directional chatoyancy, rather than tiger’s eye’s uniform parallel bands. Common sources are Namibia and China; verify with a loupe and hardness testing before any scratch test.
More like this
