sedimentary
Flint
SiO2 (Microcrystalline Quartz / Chert)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, and typically grey, brown, or black in color.
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Physical properties
Hardness of 7 on the Mohs scale, waxy to vitreous luster, conchoidal fracture, and typically grey, brown, or black in color.
Formation & geological history
Formed through the replacement of calcium carbonate by silica-rich solutions in marine limestone or chalk deposits during the Cretaceous period.
Uses & applications
Historically used for producing sharp edges in tools and weaponry, as well as for striking sparks to create fire; currently utilized in abrasives and lapidary arts.
Geological facts
Flint is a hard, tough variety of chert that produces sharp flakes when struck, making it one of the earliest materials utilized by humans for primitive technology.
Field identification & locations
Identify in the field by its distinct conchoidal fracture, smooth waxy surface, and ability to scratch glass; commonly found embedded in chalk or limestone formations worldwide.
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Sandstone or Siltstone
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Fossiliferous Sedimentary Rock
Sedimentary limestone with invertebrate fossil imprint
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Sandstone
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Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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