metamorphic

Polished brown river pebble

Likely quartzite or weathered metabasalt; exact identification requires hardness and streak tests

AI-generated identification · may be incorrect

Fine-grained, rounded, brown-tan stone with dark green-black bands or inclusions and a polished/wet luster. Likely hardness 6–7 Mohs, nonmetallic, with no visible cleavage; composition may include quartz, feldspar, and dark amphibole or chlorite.

Identified September 9, 2026More metamorphic →

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At a glance

Common name: Polished brown river pebble
Scientific name: Likely quartzite or weathered metabasalt; exact identification requires hardness and streak tests
Category: metamorphic
Identified: September 9, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 as a polished common pebble; up to about $15–$30 if unusually attractive, locally collectible, or expertly shaped.

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 water-rounded cobble later polished or naturally smoothed by abrasion. If quartzite, it formed by metamorphism of sandstone; if metabasalt, it formed from altered volcanic rock, generally during Precambrian–Phanerozoic geological events.

Uses & applications

Suitable as a decorative pebble, paperweight, lapidary cabochon, or craft material; not distinctive enough for high-value jewelry or construction stone.

Geological facts

The image alone cannot reliably distinguish quartzite from basalt, schist, or another fine-grained metamorphic rock. A glass-scratch test and examination of a fresh edge would substantially improve identification.

Field identification & locations

Common in river gravels, glacial deposits, beaches, and landscaping stone collections. Quartzite should scratch glass and resist steel; basaltic material is usually dark, denser, and may show tiny feldspar crystals.