sedimentary
Flint / Chert Nodule
Silica (Microcrystalline Quartz), SiO2
Hardness of 7 on the Mohs scale, typically brown, gray, or black with a waxy to vitreous luster, conchoidal fracture, and no true cleavage.
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Physical properties
Hardness of 7 on the Mohs scale, typically brown, gray, or black with a waxy to vitreous luster, conchoidal fracture, and no true cleavage.
Formation & geological history
Formed through the replacement of calcium carbonate by silica-rich solutions in marine limestone or chalk environments during the Cretaceous period.
Uses & applications
Historically used for making stone tools, fire-starting strikers, and building materials; today primarily of interest to beachcombers and fossil hunters.
Geological facts
This specimen has been smoothed and shaped by wave action on a beach, giving it a distinctive pebble form while retaining the characteristic knobby or nodular texture of flint.
Field identification & locations
Found worldwide in chalk and limestone deposits, easily identified by its conchoidal fracture, waxy texture, and high hardness which easily scratches glass.
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