sedimentary

Jasper (Willow Creek/Desert style)

Silicon Dioxide (SiO2) with iron and clay impurities

Hardness: 6.5-7 (Mohs scale); Color: Olive green, tan, and beige with banding; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.9.

Hardness: 6
Color: Olive green, tan, and beige with banding
Luster: Vitreous to waxy

Identified March 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from hydrothermal solutions or volcanic ash in sedimentary environments. Its patterns are often the result of mineral-rich fluids flowing through cracks and solidifying over millions of years.

Uses & applications

Primarily used in jewelry as cabochons, pendants, and beads. Also popular for decorative stone carvings, tumbling, and as a collector's specimen due to its unique patterns.

Geological facts

Jasper is a variety of chalcedony. The name comes from the Greek 'iaspis', meaning spotted stone. It was once believed to provide protection against evil spirits and to help bring rain in drought-stricken areas.

Field identification & locations

Identify in the field by its opacity (it does not transmit light even on thin edges), its hardness (it will scratch glass), and its characteristic smooth, shell-like fracture pattern. Common locations include the USA (Idaho, Oregon), South Africa, and Brazil.

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