sedimentary
Flint
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, and typically grey, brown, or black color.
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Physical properties
Hardness of 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, and typically grey, brown, or black color.
Formation & geological history
Formed through the chemical 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, weapons, and fire-starting flint-and-steel sets; currently used in abrasives and decorative landscaping.
Geological facts
Flint is famous for striking sparks when hit against steel and for its sharp edges when fractured, which made it vital for ancient human survival.
Field identification & locations
Identify in the field by its distinctive conchoidal fracture and waxy luster, commonly found embedded in chalk cliffs and limestone beds worldwide.
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