sedimentary

Jasper

Jasper (Silica, SiO2)

Hardness: 6.5-7 (Mohs scale); Color: Brownish-red to earthy brown; Luster: Dull to waxy; Crystal structure: Microcrystalline/Trigonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.58-2.91

Hardness: 6
Color: Brownish-red to earthy brown
Luster: Dull to waxy

Identified April 17, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the deposition of silica from water or within volcanic ash flows, often occurring in hydrothermal veins or as nodules in sedimentary rocks. This specimen shows significant rounding, suggesting a history of water erosion in a riverbed or coastal environment.

Uses & applications

Used primarily as a gemstone for jewelry, in lapidary arts for cabochons and carvings, and as decorative stone in mosaics.

Geological facts

Jasper is an opaque variety of chalcedony. The name comes from the Greek word 'iaspis', meaning spotted stone. It has been used since antiquity for tools and talismans.

Field identification & locations

Identify by its opacity (even on thin edges), its hardness (will scratch glass), and its characteristic waxy luster when polished. Commonly found in riverbeds and gravel deposits worldwide.