sedimentary
Chert (likely flint)
Microcrystalline quartz, SiO₂
AI-generated identification · may be incorrectBrown, waxy-to-dull luster with a curved, shell-like conchoidal fracture; hardness about 7 Mohs, no cleavage, and cryptocrystalline structure. The small specimen appears naturally fractured or roughly knapped.
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Physical properties
Brown, waxy-to-dull luster with a curved, shell-like conchoidal fracture; hardness about 7 Mohs, no cleavage, and cryptocrystalline structure. The small specimen appears naturally fractured or roughly knapped.
Formation & geological history
Forms when silica accumulates and replaces material in sedimentary rocks, commonly limestone; its age depends on the host formation and cannot be determined from the image.
Uses & applications
Historically used for stone tools and fire-starting; today collected as a field specimen and sometimes used decoratively.
Geological facts
Chert’s sharp conchoidal edges made it valuable for prehistoric blades and arrowheads.
Field identification & locations
Look for hardness, lack of cleavage, and smooth curved fracture surfaces; chert occurs worldwide, especially in limestone and chalk regions. Image-based identification is tentative.
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