sedimentary

Flint (chert)

Microcrystalline quartz (SiO₂), a variety of chert

AI-generated identification · may be incorrect

Hardness about 7 Mohs; translucent honey-brown to dark brown, with a waxy to dull luster and no visible crystals. Breaks with sharp, curved conchoidal fractures; the pale edge may be weathered cortex.

Identified October 10, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms as silica-rich sediment or replacement nodules in limestone and chalk, commonly during diagenesis. Its exact age depends on the host rocks; chert occurs from ancient strata to geologically recent deposits.

Uses & applications

Historically used for tools, arrowheads, and fire-starting; today collected and sometimes used decoratively.

Geological facts

Its sharp conchoidal fracture made flint a valuable prehistoric tool material and later a key component of flintlock firearms.

Field identification & locations

The angular shape and sharp curved fracture surfaces are characteristic; common in chalk and limestone regions, including parts of Europe and North America. The specimen’s honey-brown color may reflect iron staining.