sedimentary
Flint
SiO2 (Cryptocrystalline Quartz)
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 as nodules in sedimentary rocks like chalk or limestone through the replacement of calcium carbonate by silica-rich solutions.
Uses & applications
Historically used for making stone tools, weapons, and fire-starting flintlocks; currently used in abrasives and decorative gravel.
Geological facts
Prehistoric humans heavily favored flint due to its ability to fracture into extremely sharp edges.
Field identification & locations
Identified easily by its distinctive conchoidal fracture and high hardness, commonly found globally in chalk and limestone formations.
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