sedimentary

Jasper (likely river-worn)

Silicon Dioxide (SiO2)

Hardness: 6.5 to 7 (Mohs scale); Color: Brownish-red with white quartz/chalcedony inclusions; Luster: Dull to waxy; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.6 – 2.9

Hardness: 6
Color: Brownish-red with white quartz/chalcedony inclusions
Luster: Dull to waxy

Identified March 24, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the microcrystalline deposition of silica, often associated with volcanic ash or sedimentary processes where mineral-rich water fills cavities. This specimen appears water-worn, smoothed by alluvial (river) or coastal transport over thousands of years.

Uses & applications

Used primarily for lapidary work, jewelry (cabochons, beads), decorative landscaping, and as a collector's stone or 'pocket stone'.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek 'iaspis', meaning 'spotted stone.' It has been used for talismans and cylindrical seals since the Neolithic period and Babylonian times.

Field identification & locations

Identify in the field by its hardness (it will scratch glass), opacity (light doesn't pass through the thickest parts), and smooth, rounded surface if found near water. Common in riverbeds, glacial tills, and desert pavements across the world.

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