sedimentary
Chert (Lithic Artifact)
Microcrystalline Quartz (SiO2)
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
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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.
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