sedimentary

Chert (Flint)

Chert (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Gray, black, brown, or white; Luster: Waxy to dull; Crystal structure: Microcrystalline/cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65

Hardness: 7 on Mohs scale
Color: Gray, black, brown, or white
Luster: Waxy to dull

Identified May 24, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed through the accumulation of silica-rich organic remains or chemical precipitation in sedimentary environments. Often found as nodules in limestone or chalk beds.

Uses & applications

Historically used for making stone tools (arrowheads, scrapers) and primitive fire-starting. Currently used in road construction, landscape gravel, and occasionally for historical replicas.

Geological facts

Flint was one of the most important minerals for early human technological development due to its ability to produce sharp edges and sparks.

Field identification & locations

Identify by its characteristic conchoidal (shell-like) fracture, extreme hardness (it will scratch glass), and waxy appearance. Commonly found in riverbeds or chalk cliffs.