sedimentary
Flint
SiO2 (Microcrystalline Quartz)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically dark gray, brown, or black with a waxy to vitreous luster and conchoidal fracture.
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Physical properties
Hardness of 7 on the Mohs scale, typically dark gray, brown, or black with a waxy to vitreous luster and conchoidal fracture.
Formation & geological history
Formed through the chemical replacement of limestone or chalk by silica-rich solutions in marine environments over millions of years.
Uses & applications
Historically used for making stone tools and fire-starting, and occasionally used in landscaping or decorative gravel.
Geological facts
Prehistoric humans heavily favored flint for knapping sharp blades and arrowheads due to its predictable conchoidal fracture.
Field identification & locations
Identified by its sharp edges when broken, waxy luster, and ability to spark when struck against steel. Found globally in chalk and limestone deposits.
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