metamorphic

Polished gray stone, likely quartzite or river-worn granite

Tentatively quartzite (mostly microcrystalline SiO₂); exact identification is uncertain from the photograph

AI-generated identification · may be incorrect

Smooth, rounded, and weakly lustrous with gray, tan, and brown mottling. Likely hardness about 6.5–7 Mohs, with no obvious cleavage; quartzite has a granular interlocking crystal texture, while granite would show visible quartz and feldspar grains.

Identified September 9, 2026More metamorphic →

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At a glance

Common name: Polished gray stone, likely quartzite or river-worn granite
Scientific name: Tentatively quartzite (mostly microcrystalline SiO₂); exact identification is uncertain from the photograph
Category: metamorphic
Identified: September 9, 2026
Method: Standard

AI Estimated Value

Usually $1–$10 as an unidentified pebble or tumbled stone; potentially $10–$30 if attractively patterned and sold as a decorative specimen.

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 naturally water-worn and possibly polished; quartzite forms when sandstone is metamorphosed under heat and pressure, commonly during Precambrian to younger mountain-building events. A river pebble could also be weathered granite or another silicate rock.

Uses & applications

Suitable as a decorative pebble, paperweight, or craft/tumbling material; not gem-quality based on the visible appearance. Common specimens are generally inexpensive.

Geological facts

The image does not show diagnostic crystal faces or grain detail, so mineral identification is provisional. A glass-scratch test and close inspection with magnification would distinguish quartzite from softer rocks.

Field identification & locations

Common in river gravels and glacial deposits worldwide. If it scratches ordinary glass and shows fused-looking grains, quartzite is likely; visible pink/white feldspar and translucent quartz suggest granite. Avoid destructive testing if it is a valued specimen.