sedimentary

Fine-grained gray sandstone or quartz-rich sedimentary pebble

Likely quartz arenite or lithic sandstone; exact identification requires microscopy or testing

AI-generated identification · may be incorrect

Light gray, dull to slightly granular surface with very fine sand-sized grains and scattered rusty iron-oxide spots; likely hardness around 6–7 if quartz-rich, with no visible cleavage. Specific gravity is approximately 2.5–2.7.

Identified August 7, 2026More sedimentary →

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Physical properties

Formation & geological history

Probably formed by compaction and cementation of sand in an ancient river, beach, or shallow-marine environment, then naturally weathered into a pebble. Its precise geological age and cement are indeterminate from the image.

Uses & applications

Common sandstone is used for building stone, paving, landscaping, and aggregate; this small specimen has little commercial value but may be useful for teaching or casual collecting.

Geological facts

The faint granular texture and rounded shape favor sandstone over a crystalline igneous rock, though weathered fine-grained quartzite or graywacke are alternatives.

Field identification & locations

Check with a 10× lens for individual sand grains, test hardness against glass, and apply dilute hydrochloric acid for carbonate cement or grains. Common in streambeds, beaches, gravel deposits, and sedimentary outcrops.