sedimentary
Chert (Flint)
Chert (Cryptocrystalline Silica/SiO2)
Hardness: 7 on Mohs scale; Color: Gray to black; Luster: Waxy to dull; Structure: Cryptocrystalline; Fracture: Conchoidal (very sharp edges); Cleavage: None
- Hardness
- 7 on Mohs scale
- Color
- Gray to black
- Luster
- Waxy to dull
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Physical properties
Hardness: 7 on Mohs scale; Color: Gray to black; Luster: Waxy to dull; Structure: Cryptocrystalline; Fracture: Conchoidal (very sharp edges); Cleavage: None
Formation & geological history
Formed through the accumulation of silica-rich microfossils or chemical precipitation in sedimentary basins. The location (Antalya region, Turkey) is known for limestone-rich topography where chert nodules commonly form within carbonate layers during diagenesis.
Uses & applications
Historically used for making stone tools and fire-starting. Modern uses include decorative gravel and as a high-quality abrasive in some industrial processes.
Geological facts
Because of its conchoidal fracture pattern, it can be flapped into razor-sharp edges, making it the primary material for prehistoric arrowheads and scrapers. The specimen shows a clear 'cortex' (the light-colored outer weathering rind).
Field identification & locations
Look for a waxy luster and smooth, shell-like (conchoidal) breaks. In the Antalya region, it is frequently found embedded in or eroded out of Mesozoic limestone formations. It will easily scratch glass.
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