sedimentary
Flint
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, colors range from grey to dark brown, waxy to vitreous luster, conchoidal fracture with no cleavage.
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Physical properties
Hardness of 7 on the Mohs scale, colors range from grey to dark brown, waxy to vitreous luster, conchoidal fracture with no cleavage.
Formation & geological history
Formed through the chemical replacement of calcium carbonate in limestone or chalk by silica-rich groundwaters over millions of years.
Uses & applications
Historically used for making stone tools, arrowheads, and fire-starting flintlocks; currently used in abrasives and decorative landscaping.
Geological facts
Prehistoric humans heavily prized flint for its sharp conchoidal fracture when knapped, making it essential for ancient survival technology.
Field identification & locations
Identify in the field by its waxy luster, conchoidal fracture, and ability to spark when struck against steel. Found globally within chalk and limestone formations.
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Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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