sedimentary

Jasper (Red Jasper)

Silicon Dioxide (SiO₂)

AI-generated identification · may be incorrect

Hardness: 6.5 - 7 on Mohs scale; Color: Reddish-brown (oxidized iron); Luster: Vitreous to dull; Crystal structure: Trigonal (microcrystalline quartz); Cleavage: None/Conchoidal fracture; Specific gravity: 2.58 - 2.91

Hardness: 6
Color: Reddish-brown (oxidized iron)
Luster: Vitreous to dull

Identified March 29, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from silica-rich groundwater or volcanic ash that fills fissures or replaces organic matter over millions of years; often found in sedimentary environments or as rounded pebbles in stream beds.

Uses & applications

Commonly used in lapidary work for cabochons, beads, and stone carvings; historically used for seals and amulets; occasionally used as an ornamental building material.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek 'iaspis', meaning 'spotted stone.' It has been a popular gemstone since ancient Mesopotamian and Egyptian civilizations.

Field identification & locations

Identify by its waxy-to-dull luster when unpolished and its inability to be scratched by a steel knife. It is commonly found in gravel pits, deserts, and beaches worldwide. Collectors looks for smooth, water-worn pebbles.