sedimentary
Chert (Flint)
Chert (SiO2)
AI-generated identification · may be incorrectHardness: 7 Mohs; Color: Tan, beige, and white banding; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.5-2.8
- Hardness
- 7 Mohs
- Color
- Tan, beige, and white banding
- Luster
- Waxy to dull
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Physical properties
Hardness: 7 Mohs; Color: Tan, beige, and white banding; Luster: Waxy to dull; Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.5-2.8
Formation & geological history
Formed through the accumulation of silica-rich organic remains or chemical precipitation in marine environments; commonly found in limestone or chalk beds.
Uses & applications
Historically used for stone tools and weapons (arrowheads); currently used in road construction, landscaping, and sometimes as a flux in glass making.
Geological facts
Chert has been used by humans for millions of years because its conchoidal fracture creates extremely sharp edges; it is chemically identical to quartz but with a microcrystalline structure.
Field identification & locations
Identify by its smooth, waxy feel and sharp, curved edges when broken. It is harder than steel and will scratch glass. Found globally in sedimentary basins.
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