sedimentary
Chert (Jasper / Flint Pebble)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness 6.5–7 on the Mohs scale, earthy to dull waxy luster, conchoidal fracture, and a reddish-brown to dark brown coloration.
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Physical properties
Hardness 6.5–7 on the Mohs scale, earthy to dull waxy luster, conchoidal fracture, and a reddish-brown to dark brown coloration.
Formation & geological history
Formed via biochemical precipitation or silica replacement in sedimentary environments, smoothed into an oblong pebble through fluvial or wave erosion.
Uses & applications
Used historically for knapped stone tools and fire-starting; primarily collected today as decorative gravel or tumbled stones.
Geological facts
Due to its high silica content, chert produces sparks when struck sharply against carbon steel, a property utilized by humans for millennia.
Field identification & locations
Identified by its high hardness, smooth rounded exterior, absence of cleavage, and dull earthy appearance in gravel beds or stream deposits.
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Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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