sedimentary
Chert / Flint
Chert (SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: Tan, brown, or light yellow; Luster: Dull to waxy; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.7
- Hardness
- 7 on Mohs scale
- Color
- Tan, brown, or light yellow
- Luster
- Dull to waxy
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Physical properties
Hardness: 7 on Mohs scale; Color: Tan, brown, or light yellow; Luster: Dull to waxy; Crystal Structure: Microcrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.6-2.7
Formation & geological history
Formed through the accumulation of silica-rich organic remains or chemical precipitation in sedimentary basins. Often occurs as nodules in limestone or chalk.
Uses & applications
Historically used for stone tools due to sharp edges; currently used for construction aggregate, decorative landscaping, and occasionally lapidary art.
Geological facts
Flint is a variety of chert. It was one of the most important minerals for early humans, used to create arrowheads, scrapers, and to start fires.
Field identification & locations
Identified by its extremely sharp, curved (conchoidal) edges when broken and its ability to scratch glass. Found worldwide, particularly in riverbeds and limestone outcrops.
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