sedimentary
Chert (Flint)
Chert (Silicon Dioxide, SiO2)
AI-generated identification · may be incorrectHardness: 7 on Mohs scale; Color: white, grey, brown; Luster: vitreous to waxy; Crystal structure: cryptocrystalline; Cleavage: none (conchoidal fracture); Specific gravity: 2.65
- Hardness
- 7 on Mohs scale
- Color
- white, grey, brown
- Luster
- vitreous to waxy
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Physical properties
Hardness: 7 on Mohs scale; Color: white, grey, brown; Luster: vitreous to waxy; Crystal structure: cryptocrystalline; Cleavage: none (conchoidal fracture); Specific gravity: 2.65
Formation & geological history
Formed from the accumulation of siliceous remains of organisms like diatoms or radiolarians, or through chemical precipitation in marine environments. Prevalent in sedimentary strata like limestone.
Uses & applications
Historically used for stone tools and weapons (arrowheads); currently used in construction as road stone, in ceramics, and as fire-starting flints.
Geological facts
Chert is so hard it can scratch glass and steel. It was one of the most vital materials for early humans because of its predictable fracture patterns and sharp edges.
Field identification & locations
Identify by its waxy texture and shell-like (conchoidal) fractures. Found worldwide in nodules or layers within sedimentary rocks. A key find for arrowhead hunters.
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