sedimentary
Chert
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically brown to gray, waxy to vitreous luster, conchoidal fracture, and amorphous or cryptocrystalline structure.
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Physical properties
Hardness of 7 on the Mohs scale, typically brown to gray, waxy to vitreous luster, conchoidal fracture, and amorphous or cryptocrystalline structure.
Formation & geological history
Formed through the chemical precipitation of silica from aqueous solutions or the accumulation of siliceous skeletal remains of microscopic organisms in marine environments.
Uses & applications
Historically used for making stone tools and arrowheads due to its sharp conchoidal fracture; occasionally used as a decorative stone or in lapidary work.
Geological facts
Chert is extremely durable and weather-resistant, often surviving long periods of erosion to form durable pebbles in riverbeds.
Field identification & locations
Identify by its distinctive conchoidal fracture, waxy luster, and high hardness that easily scratches glass; found globally in limestone and chalk formations.
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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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