sedimentary
Chert Nodule
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, earthy to waxy luster, conchoidal fracture, and typically brown, gray, or tan in color.
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Physical properties
Hardness of 7 on the Mohs scale, earthy to waxy luster, conchoidal fracture, and typically brown, gray, or tan in color.
Formation & geological history
Formed in marine environments through the replacement of calcium carbonate by silica-rich solutions during diagenesis.
Uses & applications
Historically used for prehistoric stone tools and weaponry due to its sharp conchoidal fracture; currently used for decorative landscaping and tumbling.
Geological facts
Chert nodules often weather out of limestone and chalk formations, leaving durable, rounded pebble-like shapes.
Field identification & locations
Identify by its extreme hardness, waxy luster, and sharp-edged conchoidal breakage. Found worldwide in sedimentary rock formations.
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