sedimentary

Chert (specifically Yellow Jasper variety)

Silicon Dioxide (SiO2)

AI-generated identification · may be incorrect

Hardness: 6.5-7 on Mohs scale. Color: Ochre yellow to tan. Luster: Waxy to dull. Crystal structure: Cryptocrystalline (microscopic quartz). Cleavage: None (conchoidal fracture). Specific gravity: 2.6-2.7.

Hardness: 6
Color: Ochre yellow to tan
Luster: Waxy to dull

Identified June 15, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich microfossils or precipitation from hydrothermal fluids. This specimen appears to be a fragment showing a conchoidal fracture pattern typical of silica-based sedimentary rocks.

Uses & applications

Historically used for stone tools (knapping). Currently used for lapidary work, jewelry, landscaping, and as a component in construction aggregate.

Geological facts

Yellow jasper was historically associated with protection and spiritual endurance. It is essentially a variety of chert that is opaque due to high iron oxide (limonite) content.

Field identification & locations

Identify in the field by its waxy texture and sharp, curved (conchoidal) edges when broken. It will scratch glass but cannot be scratched by a steel knife. Commonly found in riverbeds and limestone formations.