sedimentary
Flint / Chert Nodule
Microcrystalline quartz (SiO2)
Hardness of 7 on the Mohs scale, waxy to dull luster, conchoidal fracture, variable colors including white, grey, brown, and tan, cryptocrystalline crystal structure.
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Physical properties
Hardness of 7 on the Mohs scale, waxy to dull luster, conchoidal fracture, variable colors including white, grey, brown, and tan, cryptocrystalline crystal structure.
Formation & geological history
Formed through the replacement of calcium carbonate by silica-rich solutions in marine limestone or chalk environments, typically during the Cretaceous period.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire; currently used in abrasives, ceramic manufacturing, and as ornamental landscaping or lapidary collection specimens.
Geological facts
Flint was one of the earliest materials utilized by human ancestors to create sharp tools and weapons due to its predictable conchoidal fracture pattern.
Field identification & locations
Easily identified by its characteristic conchoidal fracture, sharp edges when broken, hardness capable of scratching glass, and waxy luster. Commonly found in chalk and limestone formations worldwide.
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