sedimentary
Flint
Cryptocrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on Mohs scale, typically gray to dark brown with a waxy luster and conchoidal fracture.
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Physical properties
Hardness of 7 on Mohs scale, typically gray to dark brown with a waxy luster and conchoidal fracture.
Formation & geological history
Formed through the chemical replacement of limestone or chalk by silica-rich groundwaters during the Cretaceous period.
Uses & applications
Historically used for prehistoric stone tools and fire-starting; currently utilized in decorative landscaping and abrasive grit.
Geological facts
Flint produces sparks when struck against steel due to its high hardness and brittle fracture pattern.
Field identification & locations
Identify by its smooth water-worn exterior, conchoidal fracture exposing dark interior, and ability to scratch glass. Commonly found in chalk deposits worldwide.
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