sedimentary

Jasper

Silicon dioxide (SiO2) with impurities

Hardness: 6.5-7 on Mohs scale; Color: Reddish-brown with variegated patterns; Luster: Dull to greasy; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.58-2.91

Hardness: 6
Color: Reddish-brown with variegated patterns
Luster: Dull to greasy

Identified June 21, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the deposition of silica from water-rich environments, often associated with volcanic ash or sedimentary processes where fine-grained materials become petrified over millions of years.

Uses & applications

Commonly used for lapidary work, decorative cabochons in jewelry, ornamental carvings, and as a popular specimen for rock tumbling and metaphysical collecting.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning spotted stone, referring to its typically multicolored or mottled appearance.

Field identification & locations

Identify in the field by its opacity (even on thin edges), its hardness (will scratch glass), and its smooth, waxy fracture. Often found in riverbeds and coastal areas.