sedimentary
Flint
SiO2 (Microcrystalline Quartz)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, dark grey to black color, waxy to vitreous luster, and conchoidal fracture.
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Physical properties
Hardness of 7 on the Mohs scale, dark grey to black color, waxy to vitreous luster, and conchoidal fracture.
Formation & geological history
Formed through the replacement of calcium carbonate in limestone by silica-rich solutions during the Cretaceous period.
Uses & applications
Historically used for making stone tools and fire-starting; currently utilized in decorative gravel and industrial ball mills.
Geological facts
Flint is a hard variety of the mineral quartz and produces sparks when struck against steel due to its high hardness.
Field identification & locations
Identified by its conchoidal fracture and waxy luster, commonly found as nodules within chalk or limestone 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
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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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