sedimentary
Flint
SiO2 (Cryptocrystalline Quartz)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically grey, brown, or black with a waxy to vitreous luster and conchoidal fracture.
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Physical properties
Hardness of 7 on the Mohs scale, typically grey, brown, or black with a waxy to vitreous luster and conchoidal fracture.
Formation & geological history
Formed through the chemical replacement of limestone or chalk by silica-rich groundwaters in marine environments.
Uses & applications
Historically used for making stone tools and fire-starting; currently used for landscaping and decorative aggregate.
Geological facts
Flint produces sparks when struck against steel due to its high hardness, making it vital for early firearms and fire creation.
Field identification & locations
Identify by its distinct conchoidal fracture, sharp edges when broken, and waxy luster; commonly found within chalk deposits worldwide.
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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
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Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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