sedimentary

Brown flint (chert)

Microcrystalline quartz (SiO₂), likely iron-stained flint

AI-generated identification · may be incorrect

Hardness about 7 Mohs; brown with pale translucent edges and a waxy to vitreous luster. Very fine-grained, without visible crystals or cleavage; breaks with curved, sharp conchoidal fractures.

Identified October 4, 2026More sedimentary →

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Physical properties

Hardness about 7 Mohs; brown with pale translucent edges and a waxy to vitreous luster. Very fine-grained, without visible crystals or cleavage; breaks with curved, sharp conchoidal fractures.

Formation & geological history

Forms when silica precipitates or replaces material in sedimentary rocks, often limestone or chalk. The exact age and source cannot be determined from the image.

Uses & applications

Used historically for stone tools and sparks; attractive pieces may be kept as curiosities or used in lapidary work.

Geological facts

Flint is a variety of chert and was widely fashioned into prehistoric blades, scrapers, and projectile points.

Field identification & locations

The small, angular brown specimen appears consistent with flint, identified by its glassy edges and conchoidal fracture. Flint occurs in sedimentary deposits worldwide; a fresh broken surface is often more diagnostic.