sedimentary

Weathered quartz-rich pebble

Likely quartzite or silicified sandstone; composition chiefly microcrystalline quartz (SiO₂) with iron-oxide staining

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; rounded gray-brown surface with white patches, dull to slightly vitreous luster, massive texture, and no obvious cleavage. Exact identification is limited by the weathered, tumbled appearance and lack of scale or tests.

Identified August 26, 2026More sedimentary →

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At a glance

Common name: Weathered quartz-rich pebble
Scientific name: Likely quartzite or silicified sandstone; composition chiefly microcrystalline quartz (SiO₂) with iron-oxide staining
Category: sedimentary
Identified: August 26, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 as a common pebble; perhaps $10–$30 if unusually attractive, polished, or provenance-documented.

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 naturally rounded stream or beach cobble formed by erosion and transport; quartzite originates from metamorphosed sandstone, whereas silicified sandstone forms when silica cements sediment. Its precise geological age and provenance cannot be determined photographically.

Uses & applications

Suitable as a decorative stone, landscaping pebble, or teaching specimen; not typically used as gem material unless it has attractive patterning or polish.

Geological facts

The brown coloration is likely limonite/goethite, produced by oxidation of iron-bearing minerals or groundwater staining. A steel file should not easily scratch quartz-rich material, while glass may be scratched by it.

Field identification & locations

Common in rivers, beaches, gravel deposits, and glacial sediments worldwide; look for granular quartz, strong durability, rounded edges, and resistance to scratching. Acid reaction would be absent unless carbonate minerals are present.