sedimentary

Rounded chert or chalcedony pebble

Microcrystalline quartz (SiO₂), possibly silicified limestone or agate-like chalcedony

AI-generated identification · may be incorrect

Opaque cream, tan, and gray-brown pebble with a dull to faintly waxy luster and likely conchoidal fracture; quartz hardness is about 7 Mohs, with no visible cleavage and specific gravity near 2.6. The surface appears naturally weathered rather than polished.

Identified August 11, 2026More sedimentary →

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Physical properties

Formation & geological history

Likely formed by silica replacing or filling cavities in sedimentary rock, then released and rounded by stream or shoreline transport; its exact geological age cannot be determined from the image. Common settings include river gravels, beaches, and weathered limestone regions.

Uses & applications

Usually a low-cost collectible or lapidary rough; suitable for tumbling, cabochons, and small decorative objects, but not generally used as an architectural stone in this form.

Geological facts

Chert and chalcedony can look very similar in hand photographs; translucency at thin edges and a sharp conchoidal break support chalcedony. A steel file should not scratch it, while quartz should scratch ordinary glass.

Field identification & locations

Common worldwide, especially in sedimentary terrains; inspect fresh broken surfaces, hardness, and translucency for identification. Exact identification would require a close examination or testing.