sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to brown and black.
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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 black.
Formation & geological history
Formed through the chemical precipitation of silica-rich fluids or accumulation of siliceous skeletal remains in marine environments over millions of years.
Uses & applications
Historically used for making stone tools and fire-starting implements due to its sharp edges when fractured.
Geological facts
Chert forms nodules within limestone and chalk deposits and was a vital resource for prehistoric human toolmakers.
Field identification & locations
Identified easily by its distinctive conchoidal fracture and high hardness that scratches glass; commonly found in sedimentary rock formations worldwide.
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