sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, earthy to waxy luster, conchoidal fracture, and colors ranging from gray to brown.
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Physical properties
Hardness of 7 on the Mohs scale, earthy to waxy luster, conchoidal fracture, and colors ranging from gray to brown.
Formation & geological history
Formed through the chemical precipitation of silica from aqueous solutions or the accumulation of siliceous skeletal remains over millions of years.
Uses & applications
Historically used for making stone tools and weapons due to its sharp conchoidal fracture; occasionally used in decorative landscaping.
Geological facts
Chert has been utilized by humans for over two million years to create flint tools, arrowheads, and spark-producing fire starters.
Field identification & locations
Identify in the field by its hard, glass-like conchoidal fracture and lack of effervescence with acid. Commonly found within limestone formations.
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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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Sandstone
Arenite
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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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