sedimentary

Chert or flint fragment

Microcrystalline quartz (SiO₂), likely chalcedony/chert

AI-generated identification · may be incorrect

Typically 6.5–7 Mohs hardness, very fine-grained, waxy to dull luster, white to pale gray, and conchoidal fracture; no visible cleavage. The chipped edges and uniform texture fit chert, though the image alone cannot distinguish it confidently from quartzite or a weathered silica-rich material.

Identified August 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms mainly by silica replacement or accumulation of microscopic silica from marine organisms in sedimentary rocks, commonly during the Paleozoic–Cenozoic. Weathering can release resistant fragments into soil and gravel.

Uses & applications

Used historically for sharp tools, arrowheads, and fire-starting; today it is mainly a teaching or collectible specimen, with limited aggregate use.

Geological facts

Fresh fractures are commonly sharp and curved, producing a glasslike edge. Flint is generally a dark or colored variety of chert, while this pale specimen is more appropriately called light-colored chert or chalcedonic silica.

Field identification & locations

Look for hardness sufficient to scratch glass, lack of cleavage, a smooth waxy surface, and conchoidal fracture. Common worldwide, especially in limestone and chalk regions; value is usually $1–$10 for a small ordinary fragment, or $10–$50 if it is an attractive worked or unusual specimen.