sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 Mohs; Color: reddish-brown, yellow, ochre; Luster: vitreous to waxy; Structure: microcrystalline quartz; Cleavage: none (conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: reddish-brown, yellow, ochre
Luster: vitreous to waxy

Identified June 8, 2026More sedimentary →

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; Color: reddish-brown, yellow, ochre; Luster: vitreous to waxy; Structure: microcrystalline quartz; Cleavage: none (conchoidal fracture); Specific gravity: 2.58-2.91

Formation & geological history

Formed from the hydrothermal precipitation of silica-rich solutions in sedimentary rocks or volcanic ash. This specific piece shows significant iron oxide staining and weathering typical of river-rolled or surface-collected nodules.

Uses & applications

Polishing for cabochons, lapidary work, decorative stone, and historically used for stone tools and seals.

Geological facts

Jasper is a variety of chalcedony that is opaque due to the inclusion of mineral impurities. The name comes from the Greek 'iaspis', meaning 'spotted stone'.

Field identification & locations

Identify by its hardness (will scratch glass), opacity, and smooth, almost greasy surface when wet. Commonly found in gravel beds, desert washes, and near volcanic outcrops.