metamorphic

Tumbled quartzite or quartz-rich river pebble

Quartzite, predominantly microcrystalline quartz (SiO₂), with iron-oxide and possible chlorite/epidote staining

AI-generated identification · may be incorrect

Hardness about 7 Mohs; pale gray-white, opaque to slightly translucent, with reddish-brown and greenish surface staining; vitreous to dull luster and no obvious cleavage. The rounded shape and smooth surface indicate natural water wear or tumbling.

Identified September 15, 2026More metamorphic →

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At a glance

Common name: Tumbled quartzite or quartz-rich river pebble
Scientific name: Quartzite, predominantly microcrystalline quartz (SiO₂), with iron-oxide and possible chlorite/epidote staining
Category: metamorphic
Identified: September 15, 2026
Method: Standard

AI Estimated Value

About $1–$10 as a common pebble or lapidary specimen; potentially $10–$30 if unusually attractive, polished, or locality-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

Likely formed when quartz-rich sandstone recrystallized under metamorphic heat and pressure, commonly during Precambrian to younger mountain-building events; the specimen was later eroded into a pebble.

Uses & applications

Used as crushed stone, aggregate, paving, and durable building material; attractive pieces are collected or polished, though this example is not typically gem-grade.

Geological facts

Quartzite commonly resists weathering better than surrounding rocks, producing rounded stream cobbles. Iron oxides create the rusty brown patches, while green coloration may reflect chlorite or epidote.

Field identification & locations

Identify by its very high hardness, granular quartz texture, lack of cleavage, and inability to scratch with a steel knife; it should scratch ordinary glass. Common in mountain belts, glacial deposits, and river gravels.