sedimentary

Likely chert (flint) pebble

Microcrystalline quartz (SiO₂), commonly called chert; identification is tentative from the image

AI-generated identification · may be incorrect

Opaque, cream-to-tan, dull-weathered surface; chert has Mohs hardness about 7, a waxy-to-dull luster, and no cleavage. The specimen appears rounded and fine-grained, with no visible crystals.

Identified October 4, 2026More sedimentary →

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Physical properties

Opaque, cream-to-tan, dull-weathered surface; chert has Mohs hardness about 7, a waxy-to-dull luster, and no cleavage. The specimen appears rounded and fine-grained, with no visible crystals.

Formation & geological history

Chert forms when silica accumulates or replaces sediment, often in marine settings; its age depends on the source deposit. This piece may have been naturally rounded by water or abrasion.

Uses & applications

Chert has historically been used for flaked stone tools; decorative pieces are sometimes collected, though this specimen appears modest.

Geological facts

Freshly broken chert can show a smooth, curved conchoidal fracture and sharp edges.

Field identification & locations

Look for hardness, waxy texture, and conchoidal fracture; common sources include sedimentary formations and stream or beach gravels. The photo alone cannot confirm the identification.