sedimentary

Rounded gray pebble, possibly limestone or quartzite

Uncertain; likely micritic limestone (calcite, CaCO₃) or fine-grained quartzite (quartz, SiO₂)

AI-generated identification · may be incorrect

Small, water-worn gray pebble with a matte surface and no visible crystals or layering. Likely hardness 3 if limestone or 7 if quartzite; cleavage and specific gravity cannot be determined from the image.

Identified August 16, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably naturally rounded by stream or glacial transport. The reported Pyrenees location commonly exposes limestone, sandstone, slate, and metamorphic rocks, but this photograph does not support a precise identification or age.

Uses & applications

A common field pebble with negligible market value, typically under $1; not suitable for jewelry or industrial use as an individual specimen.

Geological facts

The smooth triangular form reflects abrasion rather than crystal shape. A drop of dilute vinegar can produce fizz if it is calcite-rich limestone; no fizz suggests quartzite or another silicate rock.

Field identification & locations

Field identification requires a closer image and tests: streak, vinegar reaction, hardness against a steel knife or glass, and fresh-break texture. Estimated value: $0–$2 unless later testing reveals an unusual mineral or fossil.