sedimentary
Flint
Cryptocrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, and typically brownish-yellow or grey in color.
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Physical properties
Hardness of 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, and typically brownish-yellow or grey in color.
Formation & geological history
Formed through the chemical replacement of limestone or chalk by silica-rich groundwaters during the Cretaceous period.
Uses & applications
Historically used for making stone tools and fire-starting; currently used for decorative landscaping and historical reenactments.
Geological facts
Flint was one of the most critical materials for early human survival due to its ability to be chipped into razor-sharp edges.
Field identification & locations
Easily identified in the field by its distinct conchoidal fracture, waxy luster, and frequent white chalky cortex coating.
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