sedimentary

Chert or heavily weathered flint

Microcrystalline quartz (SiO₂), likely chert/flint

AI-generated identification · may be incorrect

Typically Mohs hardness 6.5–7, dull to waxy luster, brown to gray coloration, cryptocrystalline structure, and no visible cleavage; the specimen appears rough, weathered, and possibly iron-stained.

Identified August 8, 2026More sedimentary →

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Physical properties

Typically Mohs hardness 6.5–7, dull to waxy luster, brown to gray coloration, cryptocrystalline structure, and no visible cleavage; the specimen appears rough, weathered, and possibly iron-stained.

Formation & geological history

Chert forms when silica-rich fluids replace or cement sediment, often in limestone or as nodules, through diagenesis. Its exact geological age cannot be determined from the photograph; chert occurs from Precambrian rocks through modern sediments.

Uses & applications

Used historically for sharp-edged tools and fire-starting, and occasionally as decorative stone or aggregate; this small irregular piece has little commercial value.

Geological facts

Freshly fractured chert commonly shows a smooth, glassy surface and conchoidal fracture. The pointed shape may be natural weathering or a worked flake, but the image is insufficient to confirm human modification.

Field identification & locations

Look for conchoidal fracture, a very hard surface that scratches glass, and a waxy texture; it is commonly found in limestone beds, gravel, streambeds, and glacial deposits. Common sources include Europe, the Middle East, and widespread North American sedimentary regions.