sedimentary

Rounded quartz-rich river pebble

Likely quartzite or silicified sandstone; predominantly microcrystalline quartz (SiO₂), possibly with feldspar and iron-oxide staining

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; gray, tan, and brown with a dull to slightly waxy luster, massive texture, and no obvious cleavage. Its smooth, rounded shape indicates prolonged water abrasion; exact identification requires a hardness and acid test.

Identified September 12, 2026More sedimentary →

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At a glance

Common name: Rounded quartz-rich river pebble
Scientific name: Likely quartzite or silicified sandstone; predominantly microcrystalline quartz (SiO₂), possibly with feldspar and iron-oxide staining
Category: sedimentary
Identified: September 12, 2026
Method: Standard

AI Estimated Value

Generally $1–$10 as a common specimen; up to about $20–$50 if unusually attractive, large, or locally significant.

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

Probably a weathered and stream-rounded fragment of quartzite or strongly cemented sandstone, formed when quartz-rich sediment was lithified or metamorphosed, then exposed and transported. The original rock may range from Precambrian to much younger depending on its source region.

Uses & applications

Commonly used as landscaping stone, decorative aggregate, garden rock, and craft material; usually has little jewelry or collector value unless it displays unusual patterns or provenance.

Geological facts

The pale patches may be quartz-rich veins, weathering rinds, or surface mineral deposits. Quartz-rich rocks do not fizz with dilute hydrochloric acid, whereas carbonate-rich lookalikes such as limestone or marble generally do.

Field identification & locations

Common in riverbeds, beaches, glacial deposits, and gravel pits worldwide. A steel file should barely scratch it; a clear glass plate may be scratched, supporting quartz-rich composition.