sedimentary

Jasper

Silicon dioxide (SiO2)

Hardness: 6.5-7 (Mohs); Color: Mottled brown, tan, and white; Luster: Vitreous to dull; Crystal Structure: Microcrystalline (Trigonal); Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Mottled brown, tan, and white
Luster: Vitreous to dull

Identified April 24, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of fine-grained silica-rich sediments or volcanic ash. Over millions of years, heat and pressure silica-cement the material into a dense, opaque microcrystalline quartz.

Uses & applications

Used primarily for lapidary arts, jewelry (cabochons and beads), decorative ornaments, and as a popular specimen for rock tumbling and collection.

Geological facts

Jasper is a variety of chalcedony that contains up to 20% foreign materials, which determines its color and pattern. Historically, it was believed to have protective properties and was used by ancient civilizations for seals and talismans.

Field identification & locations

Identify in the field by its extreme hardness (cannot be scratched by a steel knife) and its smooth, waxy surface when broken. It is often found in riverbeds, desert washes, and coastal areas as rounded pebbles.