sedimentary

Jasper

Jasper (Silicon Dioxide, SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Opaque with red, brown, and yellow swirling patterns from iron inclusions. Luster: Vitreous to waxy when polished. Crystal structure: Trigonal/Microcrystalline. Cleavage: None (conchoidal fracture).

Hardness: 6
Luster: Vitreous to waxy when polished

Identified April 13, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed from the hydrothermal deposition of silica or in volcanic environments where ash and fine minerals are cemented together over millions of years. This specimen shows typical alluvial smoothing, suggesting it was tumbled by water in a river or coastal environment.

Uses & applications

Primarily used for lapidary work, jewelry (cabochons and beads), ornamentation, and as a collector's gemstone. Historically used for seals and decorative carvings.

Geological facts

Jasper is a variety of chalcedony. The name comes from the Old French word 'jaspre', meaning 'spotted or speckled stone'. It was mentioned in various ancient cultures as a protective stone meant to bring courage and strength.

Field identification & locations

Identify by its opacity (it does not transmit light even on thin edges, unlike agate), smooth waxy texture when wet/polished, and high hardness (it cannot be scratched by a steel knife). Commonly found in desert regions, riverbeds, and volcanic outcrops worldwide.