sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on Mohs scale, dull to waxy luster, conchoidal fracture, various colors including brown, gray, and white.
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Physical properties
Hardness of 7 on Mohs scale, dull to waxy luster, conchoidal fracture, various colors including brown, gray, and white.
Formation & geological history
Formed through the chemical precipitation of silica from seawater or the replacement of limestone during diagenesis over millions of years.
Uses & applications
Historically used by early humans for making stone tools and arrowheads; occasionally utilized in decorative landscaping and lapidary work.
Geological facts
Chert forms nodules or layers within sedimentary rock formations, primarily chalk or marine limestone.
Field identification & locations
Identified easily by its extreme hardness, smooth conchoidal fracture, and waxy appearance; found worldwide in sedimentary deposits.
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Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion
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Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
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Sandstone or Siltstone
Arenite (if sandstone)
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Shale
Shale (clastic sedimentary rock)
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Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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