sedimentary

Jasper

Silicon Dioxide (SiO2) with iron oxide impurities

Hardness: 6.5-7 (Mohs scale); Color: Red, yellow, brown, or green; Luster: Vitreous to dull; Crystal Structure: Microcrystalline trigonal; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Red, yellow, brown, or green
Luster: Vitreous to dull

Identified March 25, 2026More sedimentary →

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Physical properties

Formation & geological history

Primary formation occurs in silica-rich waters or volcanic ash deposits where silica precipitates, often during the Proterozoic to Cenozoic eras. The red/orange coloration is typically due to hematite or iron oxide inclusion.

Uses & applications

Extensively used in lapidary work for cabochons, beads, and ornaments. Historically used for making tools/scrapers. Highly valued for aesthetic landscape stones and meditative collecting.

Geological facts

Jasper is an opaque variety of chalcedony. In ancient times, it was called the 'supreme nurturer' and was featured in the breastplate of the Jewish High Priest. It is unique because its patterns and colors are caused by up to 20% foreign materials.

Field identification & locations

Identify by its waxy-to-dull luster when unpolished and its inability to be scratched by a steel knife. Commonly found in riverbeds, deserts, and volcanic regions globally (notably Western USA, Brazil, and India). To collect, look for heavy, dense rocks with conchoidal (shell-like) fractures.

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