sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to greenish-brown; Luster: Vitreous to dull; Crystal Structure: Trigonal (Microcrystalline); Cleavage: None (Conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Brownish-red to greenish-brown
Luster: Vitreous to dull

Identified May 21, 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 through the infiltration of silica-rich fluids into volcanic ash or fine-grained sediments during diagenesis or hydrothermal activity. Often found in Precambrian formations or as stream-worn pebbles.

Uses & applications

Commonly used for lapidary work, decorative cabochons for jewelry, small ornaments, and as a popular collected pebble for rockhounds.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Old French 'jaspre', meaning 'spotted or speckled stone'. Historically, it was used for cylinder seals and as amulets for protection.

Field identification & locations

Identify in the field by its high hardness (won't be scratched by a knife) and smooth, waxy surface when wet. Commonly found along riverbeds, glacial tills, and beaches.