sedimentary
Chert (Flint Pebble)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness 7 Mohs; waxy to dull luster with conchoidal fracture; tan to whitish-brown weathered exterior (patina); specific gravity ~2.65.
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Physical properties
Hardness 7 Mohs; waxy to dull luster with conchoidal fracture; tan to whitish-brown weathered exterior (patina); specific gravity ~2.65.
Formation & geological history
Formed via biochemical or chemical precipitation of silica within marine sediment beds, later rounded into a pebble by fluvial or coastal erosion.
Uses & applications
Historically used for knapping stone tools and fire-starting; modern use includes road aggregate and tumbled decorative stones.
Geological facts
Prehistoric humans heavily relied on flint and chert because its predictable conchoidal fracture allows creation of razor-sharp edges.
Field identification & locations
Identify by high hardness (scratches glass), smooth conchoidal fracture, and thin chalky weathered cortex; widespread in riverbeds and limestone regions.
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