sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to earthy orange; Luster: Dull to waxy; Crystal structure: Microcrystalline/Cryptocrystalline (trigonal); Cleavage: None; Specific Gravity: 2.58-2.91

Hardness: 6
Color: Brownish-red to earthy orange
Luster: Dull to waxy

Identified June 28, 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

Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to earthy orange; Luster: Dull to waxy; Crystal structure: Microcrystalline/Cryptocrystalline (trigonal); Cleavage: None; Specific Gravity: 2.58-2.91

Formation & geological history

Jasper is an opaque variety of chalcedony formed through the deposition of silica from water. Its color comes from high concentrations of iron oxides. It can form in varying environments, often associated with hydrothermal activity or as nodules in volcanic rocks and sedimentary beds.

Uses & applications

Jasper is widely used as a gemstone in jewelry, as decorative stone in lapidary work, and in historical times was used for tools and seals. It is a popular material for tumbling and ornamental carvings.

Geological facts

Jasper has been a favorite gemstone since antiquity; it was known as the 'supreme nurturer' in ancient lore. The name is derived from the Greek word 'iaspis', meaning spotted stone.

Field identification & locations

Identify in the field by its opacity (even on thin edges), its smooth, waxy feel when water-worn, and its inability to be scratched by a steel knife. It is common in riverbeds and coastal regions globally.