sedimentary

Flint (chert)

Microcrystalline quartz (SiO₂), a variety of chert

AI-generated identification · may be incorrect

Brown, opaque to slightly translucent at thin edges, with a waxy luster and irregular conchoidal fractures; Mohs hardness about 7. Typically lacks visible crystals or cleavage. The pale patches may be weathering or attached chalk/limestone.

Identified October 9, 2026More sedimentary →

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Physical properties

Formation & geological history

Forms when silica replaces or accumulates in sediment, often in marine limestone or chalk. Its age depends on the source formation; the image alone cannot determine it.

Uses & applications

Historically used for stone tools and fire-striking; today collected and sometimes fashioned into decorative objects.

Geological facts

Flint’s sharp conchoidal edges made it valuable for prehistoric blades and scrapers.

Field identification & locations

Look for a hard, fine-grained surface and curved, shell-like fracture; common in chalk and limestone regions, especially parts of Europe. The photograph supports a chert identification but not a precise locality or variety.