sedimentary

Flint (chert) flake/tool

Microcrystalline quartz (SiO₂), likely brown flint/chert

AI-generated identification · may be incorrect

Hardness ~7 Mohs; brown translucent interior with white, opaque cortex or altered edges; waxy to dull luster; cryptocrystalline, with conchoidal fracture and no cleavage. The deliberate flake shape and edge scars suggest a knapped stone artifact rather than an unworked fragment.

Identified August 19, 2026More sedimentary →

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Physical properties

Formation & geological history

Chert forms by silica replacement or accumulation in limestone and other sediments, commonly during the Paleozoic–Mesozoic. This piece was likely detached by prehistoric human percussion or pressure flaking; its exact age cannot be determined from the image.

Uses & applications

Historically used for cutting tools, scrapers, arrowheads, and fire-starting; today collected as an archaeological or lithic specimen. Not generally used commercially as decorative stone in this form.

Geological facts

The pale outer cortex contrasts with the darker interior exposed by flaking. Conchoidal ripples and sharp margins are characteristic of flint knapping, though similar breaks can occur naturally.

Field identification & locations

Identify by testing for glassy conchoidal fracture, very high hardness, and absence of visible grains or cleavage; avoid destructive testing if archaeological. Common in chalk and limestone regions, including England, France, Texas, Kansas, and many other areas.