sedimentary

Mixed tumbled gravel and quartz-rich sandstone

Primarily quartz (SiO₂), feldspar, and lithic sedimentary fragments; one piece appears to be quartz-rich sandstone

AI-generated identification · may be incorrect

The collection contains rounded, water-worn pebbles in tan, brown, white, gray, and reddish colors, plus a rough granular sandstone fragment. Quartz has Mohs hardness 7, vitreous luster, no cleavage, and specific gravity about 2.65; sandstone is variable and commonly Mohs 6–7 when quartz-rich.

Identified August 21, 2026More sedimentary →

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At a glance

Common name: Mixed tumbled gravel and quartz-rich sandstone
Scientific name: Primarily quartz (SiO₂), feldspar, and lithic sedimentary fragments; one piece appears to be quartz-rich sandstone
Category: sedimentary
Identified: August 21, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 for this mixed lot; selected polished or unusual specimens may sell for $5–$30 each.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Most pieces are likely alluvial or beach gravel transported and rounded by flowing water or waves; the sandstone formed when sand was compacted and cemented, generally over millions to hundreds of millions of years depending on source.

Uses & applications

Used as decorative gravel, landscaping material, craft material, aquarium substrate, and educational specimens; attractive polished pieces may be used in jewelry or wire-wrapped crafts.

Geological facts

The specimen is a mixed aggregate rather than one identifiable rock. Rounded grains indicate abrasion during transport, while the larger angular piece preserves sedimentary texture.

Field identification & locations

Look for visible sand grains, layering, and a gritty texture in the sandstone; quartz-rich pieces resist scratching by steel, while calcite-rich stones fizz weakly in dilute acid. Common sources include riverbeds, beaches, and commercial landscaping gravel.