sedimentary
Flint
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, typically dark grey to black or brown, waxy to vitreous luster, conchoidal fracture with no cleavage.
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Physical properties
Hardness of 7 on the Mohs scale, typically dark grey to black or brown, waxy to vitreous luster, conchoidal fracture with no cleavage.
Formation & geological history
Formed as chemical impurities precipitate out of solution in chalk or limestone beds over millions of years.
Uses & applications
Historically used for making stone tools and fire-starting; currently used in abrasives, ceramics, and lapidary arts.
Geological facts
Flint was crucial for early human survival due to its ability to be chipped into extremely sharp edges.
Field identification & locations
Identified easily by its conchoidal fracture, waxy luster, and high hardness that scratches glass.
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