sedimentary
Flint
Microcrystalline quartz (SiO2)
AI-generated identification · may be incorrectHardness of 7 on the Mohs scale, dark gray to black color with a waxy to vitreous luster, conchoidal fracture, and cryptocrystalline structure.
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Physical properties
Hardness of 7 on the Mohs scale, dark gray to black color with a waxy to vitreous luster, conchoidal fracture, and cryptocrystalline structure.
Formation & geological history
Forms as nodules within sedimentary rocks like chalk or limestone through the replacement of calcium carbonate by silica-rich solutions.
Uses & applications
Historically used for making stone tools, arrowheads, and fire-starting flint-lock mechanisms; currently utilized for decorative landscaping and abrasive grit.
Geological facts
Flint was one of the earliest materials manipulated by early humans to create sharp cutting tools due to its predictable conchoidal fracture.
Field identification & locations
Identify in the field by its dark color, smooth weathered cortex, conchoidal fracture pattern, and ability to scratch glass.
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