sedimentary

Chert (likely flint)

Microcrystalline quartz (SiO₂), a variety of chert

AI-generated identification · may be incorrect

Opaque, honey-brown to tan with a dull, weathered surface and curved conchoidal-looking fracture; quartz hardness is about 7 Mohs, with no cleavage. The image alone cannot confirm the material or its exact variety.

Identified October 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Chert forms when silica accumulates and replaces or fills sediment in sedimentary settings; its age varies widely with the host formation.

Uses & applications

Historically used for sharp-edged tools and fire-starting; today it is mainly collected or used decoratively.

Geological facts

Flint is a dark or colored variety of chert, and freshly fractured chert can produce very sharp edges.

Field identification & locations

Look for a hard, fine-grained, non-crystalline texture and curved fracture surfaces; common in sedimentary terrains worldwide. Estimated value: about $1–$10 for a small, ordinary fragment.