sedimentary

Chert (Lithic Artifact)

Microcrystalline Quartz (SiO2)

AI-generated identification · may be incorrect

Hardness: 7 on Mohs scale; Color: Brownish-tan with weathered patina; Luster: Dull to waxy; Texture: Fine-grained with conchoidal (shell-like) fracture patterns; Opaque.

Hardness: 7 on Mohs scale
Color: Brownish-tan with weathered patina
Luster: Dull to waxy

Identified July 17, 2026More sedimentary →

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Physical properties

Hardness: 7 on Mohs scale; Color: Brownish-tan with weathered patina; Luster: Dull to waxy; Texture: Fine-grained with conchoidal (shell-like) fracture patterns; Opaque.

Formation & geological history

Formed as nodules or beds in limestone or chalk through the accumulation of silica-rich marine organisms (like diatoms) and subsequent lithification. This specimen shows evidence of percussion flaking from human tool-making.

Uses & applications

Historically used by prehistoric cultures for tools like arrowheads, scrapers, and knives due to its sharp edges; currently valued as an archaeological and geological collectible.

Geological facts

Chert is so durable that it can survive for thousands of years in the soil. When struck against steel, it produces sparks, leading to its common name and use as flint.

Field identification & locations

Identify in the field by look for 'negative bulbs of percussion' (scalloped indentations) and a sharp, glass-like edge. Common in limestone-rich regions and riverbeds.