sedimentary

Yellow Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

AI-generated identification · may be incorrect

Hardness: 6.5-7 (Mohs); Color: Mustard yellow to brownish-yellow; Luster: Vitreous to waxy; Crystal structure: Trigonal (microcrystalline); Cleavage: None (conchoidal fracture); Specific gravity: 2.6-2.9

Hardness: 6
Color: Mustard yellow to brownish-yellow
Luster: Vitreous to waxy

Identified June 28, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the infiltration of silica-rich fluids into sediment or volcanic ash, eventually hardening into microcrystalline quartz. Usually dates back to millions of years ago in volcanic or sedimentary environments.

Uses & applications

Widely used as a gemstone for jewelry, decorative carvings, and in alternative healing practices (metaphysical uses). Historically used for tools due to its durability.

Geological facts

The yellow color is specifically caused by the presence of iron oxide (goethite or limonite). It is often found as smooth water-worn pebbles in riverbeds or coastal areas.

Field identification & locations

Identify in the field by its opaque nature, smooth waxy texture, and its inability to be scratched by a steel knife. Common in the Western United States, South Africa, and Brazil.