sedimentary (chemical/biological origin) or volcanic-related metamorphic

Jasper (Wonderstone/Banded Jasper)

Silicon Dioxide (SiO2) with iron oxide impurities

Hardness: 6.5-7 (Mohs scale); Color: Variegated red, tan, orange, and gray bands; Luster: Dull to waxy; Structure: Microcrystalline quartz; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Variegated red, tan, orange, and gray bands
Luster: Dull to waxy

Identified March 6, 2026More sedimentary (chemical/biological origin) or volcanic-related metamorphic →

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Physical properties

Formation & geological history

Formed from the deposition of silica-rich fluids in volcanic ash or sedimentary layers. The banding often results from rhythmic precipitation of iron oxides (hematite/goethite). Most common specimens date from the Cenozoic era.

Uses & applications

Used primarily for lapidary work, cabochons for jewelry, decorative carvings, and as a popular collector's specimen for its aesthetic patterns.

Geological facts

This specific banding pattern is often colloquially called 'Wonderstone' if it comes from Rhyolitic ash deposits. Its colors are dictated by the oxidation state of the iron content within the silica matrix.

Field identification & locations

Identify in the field by its smooth, shell-like (conchoidal) fracture and its inability to be scratched by a steel knife. Commonly found in desert regions of the Western United States (Utah, Nevada, Oregon).

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