sedimentary
Chert
Microcrystalline Quartz (SiO2)
Hardness: 6.5-7, Color: Gray, brown, black, Luster: Dull to waxy, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture)
- Hardness
- 6
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Physical properties
Hardness: 6.5-7, Color: Gray, brown, black, Luster: Dull to waxy, Crystal Structure: Microcrystalline, Cleavage: None (conchoidal fracture)
Formation & geological history
Formed from silica-rich fluids in sedimentary environments, often occurring as nodules or beds in limestone or chalk.
Uses & applications
Historically used for making stone tools (arrowheads, scrapers) due to its conchoidal fracture. Sometimes used in construction or as a gravel material.
Geological facts
Flint is a specific type of chert found in chalk deposits. Chert has been used by humans for millions of years to create sharp-edged tools.
Field identification & locations
Identified by its waxy luster, hardness (scratches glass), and conchoidal fracture. Commonly found in stream beds or eroding out of limestone cliffs.
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