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

Chert

Microcrystalline quartz (SiO2)

AI-generated identification · may be incorrect

Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to brown and grey.

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Physical properties

Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to brown and grey.

Formation & geological history

Formed through the chemical precipitation of silica from aqueous solutions or the accumulation of siliceous skeletal remains in marine environments.

Uses & applications

Historically used for making stone tools and weapons due to its sharp conchoidal fracture; currently used in abrasives and decorative landscaping.

Geological facts

Prehistoric humans heavily favored chert and flint for knapping arrowheads and blades because of predictable fracture mechanics.

Field identification & locations

Identify by its extreme hardness, waxy sheen, and smooth curved breakage patterns; commonly found within limestone and chalk formations worldwide.