sedimentary
Flint
Silicon dioxide (Cryptocrystalline Quartz, SiO2)
AI-generated identification · may be incorrectHardness: 7 on the Mohs scale, Color: Brownish-yellow, tan, or gray, Luster: Waxy to vitreous, Crystal structure: Microcrystalline / Cryptocrystalline, Cleavage: None (exhibits conchoidal fracture), Specific gravity: 2.60 to 2.65
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Physical properties
Hardness: 7 on the Mohs scale, Color: Brownish-yellow, tan, or gray, Luster: Waxy to vitreous, Crystal structure: Microcrystalline / Cryptocrystalline, Cleavage: None (exhibits conchoidal fracture), Specific gravity: 2.60 to 2.65
Formation & geological history
Formed by the replacement of calcium carbonate by silica-rich solutions in chalk or limestone formations during the Cretaceous period and other geological eras.
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire; currently used in abrasives, ceramics, and as a decorative stone.
Geological facts
Flint is famous for its sharp conchoidal fracture edges, making it a primary material for prehistoric stone tool technology across the globe.
Field identification & locations
Can be identified in the field by its waxy luster, conchoidal fracture patterns, and ability to spark when struck against steel. Commonly found within chalk and limestone beds worldwide.
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