sedimentary
Flint
SiO2 (Microcrystalline Quartz)
AI-generated identification · may be incorrectHardness 7 on Mohs scale, waxy luster, conchoidal fracture, opaque white to dark grey or black color.
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Physical properties
Hardness 7 on Mohs scale, waxy luster, conchoidal fracture, opaque white to dark grey or black color.
Formation & geological history
Formed by chemical replacement of limestone or chalk in marine environments during the Cretaceous period.
Uses & applications
Historically used for prehistoric stone tools and fire-starting; currently used in abrasives and ceramics.
Geological facts
Flint produces sparks when struck against steel due to its high hardness and brittle fracture.
Field identification & locations
Identify by its distinct conchoidal fracture, waxy feel, and occurrence as nodules within chalk 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
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Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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