sedimentary
Flint / Chert
Microcrystalline Quartz (SiO2)
Hardness of 7 on the Mohs scale, colors range from grey, white, to dark brown or black, waxy to vitreous luster, conchoidal fracture, no distinct crystal structure visible to the naked eye.
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Physical properties
Hardness of 7 on the Mohs scale, colors range from grey, white, to dark brown or black, waxy to vitreous luster, conchoidal fracture, no distinct crystal structure visible to the naked eye.
Formation & geological history
Formed through the replacement of calcium carbonate by silica-rich solutions in marine environments (such as chalk or limestone formations) over millions of years.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire. Today used for decorative landscaping, abrasive grits, and in specialized construction.
Geological facts
Flint was one of the earliest materials manipulated by humans to create sharp cutting edges and weapons during the Stone Age.
Field identification & locations
Easily identified in the field by its distinctive conchoidal fracture (smooth, curved breakage patterns), waxy luster, and ability to spark when struck with steel.
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