sedimentary
Flint Pebble
SiO2 (Microcrystalline Quartz / Chalcedony)
Hardness of 7 on the Mohs scale, brown to grey color, waxy to vitreous luster, cryptocrystalline structure, conchoidal fracture with no true cleavage, and a specific gravity around 2.60 to 2.65.
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Physical properties
Hardness of 7 on the Mohs scale, brown to grey color, waxy to vitreous luster, cryptocrystalline structure, conchoidal fracture with no true cleavage, and a specific gravity around 2.60 to 2.65.
Formation & geological history
Formed through the replacement of calcium carbonate by silica-rich solutions within chalk or limestone formations during the Cretaceous period, followed by weathering and wave-action tumbling on beaches.
Uses & applications
Historically used for making stone tools, arrowheads, and fire-starting flint-locks; currently used in grinding mills, road aggregate, and as decorative beach pebbles.
Geological facts
Flint is extremely durable and breaks with a very sharp conchoidal fracture, making it one of the earliest materials manipulated by early humans for weaponry and cutting tools.
Field identification & locations
Easily identified by its smooth, water-worn exterior, waxy luster, conchoidal fracture showing darker interior layers, and high hardness capable of scratching glass. Commonly found along chalk cliffs and beaches, especially in regions like southern England and northwestern Europe.
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