sedimentary
Chert Pebble / Flint
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness 7 on Mohs scale; waxy to dull luster; conchoidal fracture with mottled brown, tan, and dark gray coloration.
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Physical properties
Hardness 7 on Mohs scale; waxy to dull luster; conchoidal fracture with mottled brown, tan, and dark gray coloration.
Formation & geological history
Formed via biochemical precipitation of silica in marine environments, followed by mechanical water rounding into a smooth pebble.
Uses & applications
Commonly used historically for knapped tools and spark ignition; currently used as decorative gravel and tumbled stones.
Geological facts
Chert was essential to early human development as one of the primary stone-tool materials alongside obsidian.
Field identification & locations
Identified in gravel beds and beaches by its extreme hardness (scratches glass/steel) and smooth, rounded surface with conchoidal chips.
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