sedimentary
Flint
SiO2 (Microcrystalline Quartz / Chert)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically brown, grey, or black in color.
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Physical properties
Hardness of 7 on the Mohs scale, waxy luster, conchoidal fracture, and typically brown, grey, or black in color.
Formation & geological history
Formed through the replacement of calcium carbonate by silica-rich solutions in chalk or limestone formations during the Cretaceous period.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire; currently used in decorative aggregates and abrasive blasting.
Geological facts
Flint produces sparks when struck against steel due to iron micro-particles shearing off and igniting in the air.
Field identification & locations
Identified easily by its sharp conchoidal edges, waxy appearance, and occurrence as nodules within chalk beds.
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Sedimentary limestone with invertebrate fossil imprint
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Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
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