sedimentary
Flint
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically brown, gray, or black with a waxy to vitreous luster and conchoidal fracture.
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Physical properties
Hardness of 7 on the Mohs scale, typically brown, gray, or black with a waxy to vitreous luster and conchoidal fracture.
Formation & geological history
Formed through the chemical replacement of calcium carbonate in limestone or chalk by silica-rich solutions during the Cretaceous period.
Uses & applications
Historically used for making stone tools, arrowheads, and fire-starting flintlocks; modernly used in abrasives and decorative gravel.
Geological facts
Flint produces sparks when struck against steel due to its high hardness and brittle fracture creating micro-hotspots.
Field identification & locations
Easily identified by its sharp conchoidal edges, waxy luster, and occurrence as nodules within chalk or limestone deposits.
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Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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