sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
Hardness: 7 Mohs, Color: Grey to brownish-grey, Luster: Waxy to vitreous, Structure: Cryptocrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
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Physical properties
Hardness: 7 Mohs, Color: Grey to brownish-grey, Luster: Waxy to vitreous, Structure: Cryptocrystalline, Cleavage: None (conchoidal fracture), Specific Gravity: 2.65
Formation & geological history
Formed via chemical precipitation from silica-rich fluids or replacement of carbonate minerals in marine sedimentary environments; common in limestone or chalk beds.
Uses & applications
Historically used for stone tools and fire-starting. Currently used in road surfacing, abrasives, and as a collector specimen.
Geological facts
Flint was the primary material for the Stone Age technology due to its ability to split into razor-sharp edges. It is often found as nodules inside chalk or limestone deposits.
Field identification & locations
Identified by its extremely smooth, waxy surface and sharp conchoidal (shell-like) fracture edges. Found globally in sedimentary basins.
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