sedimentary
Chert
Microcrystalline quartz (Silicon dioxide, SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to dark gray or brown.
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Physical properties
Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and colors ranging from white to dark gray or brown.
Formation & geological history
Formed through the chemical precipitation of silica-rich fluids or accumulation of siliceous skeletal remains in deep marine environments.
Uses & applications
Historically used for making stone tools and arrowheads due to its sharp conchoidal fracture, and occasionally in abrasives.
Geological facts
Chert forms nodules or layers within limestone and chalk formations and was a primary material for ancient fire-starting.
Field identification & locations
Identified by its extreme hardness, vitreous to waxy luster, and smooth curved fracture surfaces. Found globally in sedimentary strata.
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