sedimentary
Flint / Chert
Silicon dioxide (Microcrystalline Quartz, SiO2)
Hardness of 7 on the Mohs scale, typically gray, white, brown, or black with a waxy to vitreous luster, conchoidal fracture, and no cleavage.
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Physical properties
Hardness of 7 on the Mohs scale, typically gray, white, brown, or black with a waxy to vitreous luster, conchoidal fracture, and no cleavage.
Formation & geological history
Formed in marine environments through the chemical replacement of limestone or chalk by silica-rich solutions, or through the accumulation of siliceous skeletal remains of marine organisms over millions of years.
Uses & applications
Historically used for making stone tools, weapons, and fire-starting (striking against steel). Modern uses include abrasives and ornamental landscaping.
Geological facts
Flint was one of the most important materials for early humans during the Stone Age due to its ability to be chipped into extremely sharp edges.
Field identification & locations
Easily identified by its distinctive conchoidal fracture and hardness that scratches glass. Commonly found nodular within chalk or limestone formations.
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