sedimentary
Flint
Cryptocrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, dark gray to black color with a waxy to vitreous luster, and exhibits conchoidal fracture.
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Physical properties
Hardness of 7 on the Mohs scale, dark gray to black color with a waxy to vitreous luster, and exhibits conchoidal fracture.
Formation & geological history
Forms via the replacement of calcium carbonate by silica-rich solutions within chalk or limestone formations during the Cretaceous period.
Uses & applications
Historically used for making stone tools, arrowheads, and fire-starting flint-locks; currently utilized in landscaping and abrasive grinding.
Geological facts
Prehistoric humans heavily prized flint for its sharp edges when fractured, making it essential for early technology.
Field identification & locations
Identify in the field by its dark color, smooth weathered cortex, and sharp conchoidal break surfaces; commonly found within chalk deposits worldwide.
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