Rock Identifier
Flint (Microcrystalline quartz (SiO2)) — sedimentary
sedimentary

Flint

Microcrystalline quartz (SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on Mohs scale, typically brown to grey with a waxy or vitreous luster and conchoidal fracture.

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Physical properties

Hardness of 7 on Mohs scale, typically brown to grey with a waxy or vitreous luster and conchoidal fracture.

Formation & geological history

Formed through the chemical replacement of limestone or chalk by silica-rich groundwater in marine environments.

Uses & applications

Historically used for making stone tools and fire-starting; currently used in abrasives, ceramics, and construction.

Geological facts

Flint produces sparks when struck against steel due to its high hardness, making it vital for early firearms and survival.

Field identification & locations

Identified by its sharp conchoidal fracture and waxy luster, commonly found inside chalk deposits and limestone formations worldwide.