sedimentary
Flint
Sedimentary cryptocrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically grey, brown, or black in color.
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Physical properties
Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically grey, brown, or black in color.
Formation & geological history
Formed through the chemical replacement of limestone or chalk by silica-rich groundwaters in marine environments.
Uses & applications
Historically used for making stone tools and fire-starting; currently used in decorative landscaping and abrasive grit.
Geological facts
Prehistoric humans heavily favored flint for creating sharp blades and arrowheads due to its predictable conchoidal fracture.
Field identification & locations
Identify by its waxy sheen, sharp conchoidal edges, and ability to strike sparks against steel; found worldwide in chalk deposits.
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