sedimentary
Flint
Silicon dioxide (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically gray or dark brown with a waxy or vitreous luster and conchoidal fracture.
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Physical properties
Hardness of 7 on the Mohs scale, typically gray or dark brown with a waxy or vitreous luster and conchoidal fracture.
Formation & geological history
Formed through the chemical replacement of calcium in limestone or chalk by silica-rich solutions during the Cretaceous period.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire; currently used for decorative landscaping and historical reenactments.
Geological facts
Flint was a vital resource for prehistoric humans due to its ability to fracture into extremely sharp edges.
Field identification & locations
Identified by its conchoidal fracture, sharp edges, and ability to produce sparks when struck against steel. Found globally in chalk and limestone formations.
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Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
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Sandstone or Siltstone
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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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