sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to dark brown or black.
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Physical properties
Hardness of 7 on Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to dark brown or black.
Formation & geological history
Formed through the chemical precipitation of silica from aqueous solutions or the accumulation of siliceous skeletal remains over millions of years.
Uses & applications
Historically used by early humans for making stone tools and arrowheads due to its sharp edges when fractured.
Geological facts
Chert is extremely durable and weather-resistant, often surviving long after surrounding limestone erodes away.
Field identification & locations
Identify by its distinctive conchoidal fracture and high hardness that easily scratches glass. Commonly found within limestone and chalk deposits worldwide.
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