sedimentary

Chert (likely a weathered flake)

Microcrystalline quartz (SiO₂); chert

AI-generated identification · may be incorrect

Gray-brown, dull to waxy surface with a lighter weathered rind and sharp, curved fracture surfaces. Hardness about 7 Mohs; cryptocrystalline structure, no cleavage, specific gravity about 2.6.

Identified October 4, 2026More sedimentary →

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Physical properties

Gray-brown, dull to waxy surface with a lighter weathered rind and sharp, curved fracture surfaces. Hardness about 7 Mohs; cryptocrystalline structure, no cleavage, specific gravity about 2.6.

Formation & geological history

Chert forms when silica accumulates and hardens in sedimentary settings, commonly replacing carbonate sediment; its age cannot be determined from the image. The shape may be a naturally fractured fragment or a worked stone flake.

Uses & applications

Used historically for sharp tools and fire-starting; today it is mainly a teaching or collecting specimen, with limited ornamental use.

Geological facts

Chert breaks with conchoidal fractures, producing sharp edges. A deliberate tool origin cannot be confirmed from this photograph alone.

Field identification & locations

Look for hardness sufficient to scratch glass, a smooth waxy fracture, and a pale rind; chert occurs widely in sedimentary formations. Similar-looking materials include quartzite and flint.