sedimentary
Chert (Flint / Jasper pebble)
Microcrystalline Quartz (SiO2)
AI-generated identification · may be incorrectHardness 6.5–7 on the Mohs scale, waxy to dull luster, conchoidal fracture, and yellowish-tan color with a lighter weathered rind.
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Physical properties
Hardness 6.5–7 on the Mohs scale, waxy to dull luster, conchoidal fracture, and yellowish-tan color with a lighter weathered rind.
Formation & geological history
Formed by biochemical or chemical precipitation of silica in sedimentary environments such as marine carbonate beds during the Paleozoic era.
Uses & applications
Historically used for knapping stone tools and fire-striking; modernly used as road aggregate and tumbled decorative stone.
Geological facts
Ohio designated flint (a variety of chert) as its official state gemstone due to prolific historic deposits like Flint Ridge.
Field identification & locations
Identify in the field by its superior hardness (scratches glass/steel), lack of visible grains, and smooth or conchoidal fracture. Abundant in Ohio glacial drift and gravel bars.
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