metamorphic

Pietersite

Brecciated Crocidolite in Quartz (Chalcedony)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Swirls of blue, gold, red, and dusky grey; Luster: Silky/Vitreous; Structure: Trigonal (as microcrystalline aggregate); Specific Gravity: 2.50-2.74

Hardness: 6
Color: Swirls of blue, gold, red, and dusky grey
Luster: Silky/Vitreous

Identified May 11, 2026More metamorphic →

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Physical properties

Hardness: 6.5-7 (Mohs); Color: Swirls of blue, gold, red, and dusky grey; Luster: Silky/Vitreous; Structure: Trigonal (as microcrystalline aggregate); Specific Gravity: 2.50-2.74

Formation & geological history

Formed via the silicification of crocidolite (asbestos) that has been shattered or fractured (brecciated) and cemented by silica. Original formation occurs in iron-rich sedimentary environments that underwent low-grade metamorphism.

Uses & applications

Primarily used as a semi-precious gemstone in jewelry (cabochons, pendants) and as a high-valued collector's stone for its unique chatoyancy.

Geological facts

Known as 'The Tempest Stone' because its swirling patterns resemble a storm. It was discovered by Sid Pieters in Namibia in 1962 and was later found in China in the 1990s.

Field identification & locations

Identify by the chaotic, swirling chatoyancy (unlike the parallel banding of Tiger's Eye) and vibrant blue-gold mix. Found mainly in Namibia and Henan Province, China. Collectors look for high contrast and chatoyance.