sedimentary
Chert Nodule
Sedimentary cryptocrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on Mohs scale, earthy to waxy luster, conchoidal fracture, and brownish-grey coloration.
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Physical properties
Hardness of 7 on Mohs scale, earthy to waxy luster, conchoidal fracture, and brownish-grey coloration.
Formation & geological history
Formed through the diagenetic replacement of limestone or chalk by silica-rich solutions over millions of years.
Uses & applications
Historically used by ancient humans for making stone tools, arrowheads, and spark-producing fire starters.
Geological facts
Chert is extremely durable and breaks with sharp edges, making it a primary material for prehistoric lithic technology worldwide.
Field identification & locations
Identify in the field by its distinct conchoidal fracture, smooth weathered rind, and extreme hardness that scratches glass; found globally in limestone formations.
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