sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Tan, brown, and grey with dendritic or brecciated patterns; Luster: Vitreous to waxy; Crystal Structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Tan, brown, and grey with dendritic or brecciated patterns
Luster: Vitreous to waxy

Identified July 14, 2026More sedimentary →

Explore Jasper in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Formed from the deposition of silica from water solutions or volcanic ash, occurring in sedimentary environments where iron oxides and other impurities create opaque colors and patterns. It can date from almost any geological era.

Uses & applications

Commonly used for lapidary work, jewelry (cabochons), tumbled stones, decorative ornaments, and as a popular specimen for rock tumbling enthusiasts.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek 'iaspis', meaning spotted stone. It has been used for seals and amulets since ancient Mesopotamian and Minoan civilizations.

Field identification & locations

Identify by its hardness (cannot be scratched by a steel knife) and its opacity. This tumbled specimen shows characteristic earthy tones and fine-grained texture. It is frequently found in riverbeds and coastal regions worldwide.