sedimentary
Chert (Flint)
SiO2 (Microcrystalline Quartz)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale. Color: Tan, yellowish-brown, cream with iron staining. Luster: Waxy to dull. Fracture: Conchoidal. Specific Gravity: 2.5-2.8.
- Hardness
- 7 on Mohs scale
- Color
- Tan, yellowish-brown, cream with iron staining
- Luster
- Waxy to dull
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Physical properties
Hardness: 7 on Mohs scale. Color: Tan, yellowish-brown, cream with iron staining. Luster: Waxy to dull. Fracture: Conchoidal. Specific Gravity: 2.5-2.8.
Formation & geological history
Formed in marine environment sedimentary rock layers where silica-rich fluids precipitated microcrystalline quartz, often replacing carbonates or organic materials.
Uses & applications
Historically used for making stone tools, arrowheads, and flintlock ignition systems. Today used as road aggregate, construction fill, and landscaping stone.
Geological facts
Chert breaks with a sharp, shell-like (conchoidal) fracture, which made it one of the most vital raw materials for prehistoric human technology and toolmaking worldwide.
Field identification & locations
Identified by its high hardness (scratches glass easily), waxy texture, and sharp curved edges where fractured. Very common in limestone and chalk formations worldwide.
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