sedimentary
Flint
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically gray or dark brown with a waxy to vitreous luster and conchoidal fracture.
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Physical properties
Hardness of 7 on the Mohs scale, typically gray or dark brown 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 over millions of years.
Uses & applications
Historically used for making stone tools and fire-starting; currently used in abrasives, ceramics, and lapidary collections.
Geological facts
Flint produces sparks when struck against steel due to its extreme hardness, making it vital for early firearms and survival.
Field identification & locations
Identify by its dark color, sharp conchoidal edges, and smooth nodular surface. Commonly found embedded in chalk or limestone formations.
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Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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