sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Reddish-brown, yellow, and tan due to iron inclusions; Luster: Dull to greasy; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Reddish-brown, yellow, and tan due to iron inclusions
Luster: Dull to greasy

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 through the accumulation of fine-grained silica-rich sediments or volcanic ash that undergo lithification. Often found as nodules or fillings in cracks and cavities within volcanic or sedimentary rocks over millions of years.

Uses & applications

Commonly used for lapidary work, jewelry making (cabochons), ornamental decoration, and as a collector's specimen.

Geological facts

Jasper is an opaque variety of chalcedony. Its colors are primarily derived from the oxidation of iron minerals within the stone. In ancient times, jasper was believed to provide physical strength and protection to the wearer.

Field identification & locations

Identify in the field by its opacity (it will not let light through even at thin edges, unlike quartz), its waxy feel when polished, and its characteristic smooth, curved fractures. Found in riverbeds and mountainous regions globally.