sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness: 7 Mohs scale; Color: Cream, tan, and grey banding; Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
- Hardness
- 7 Mohs scale
- Color
- Cream, tan, and grey banding
- Luster
- Waxy to vitreous
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Physical properties
Hardness: 7 Mohs scale; Color: Cream, tan, and grey banding; Luster: Waxy to vitreous; Crystal Structure: Cryptocrystalline; Cleavage: None (conchoidal fracture); Specific Gravity: 2.65
Formation & geological history
Formed through the accumulation of silica-rich organic remains or chemical precipitation in marine or groundwater environments. Often found as nodules in limestone or chalk beds.
Uses & applications
Historically used for stone tools and weapons (arrowheads); currently used in road construction, as a gemstone (jaspers/agates), and for fire-starting.
Geological facts
Chert has been used by humans for over two million years and was the primary material for the Stone Age technology due to its sharp conchoidal edges.
Field identification & locations
Identified by its extreme hardness (scratches glass), waxy texture, and shell-like (conchoidal) breaking pattern. Common in sedimentary basins worldwide.
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