sedimentary

Rounded weathered pebble, likely chert or fine-grained quartzite

Microcrystalline quartz (SiO₂), probable chert; quartzite is an alternative

AI-generated identification · may be incorrect

Gray-brown, opaque, dull to slightly waxy luster, fine-grained and rounded; quartz-rich material has Mohs hardness about 6.5–7, no visible cleavage, and conchoidal or irregular fracture. The image is insufficient for definite identification.

Identified September 9, 2026More sedimentary →

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At a glance

Common name: Rounded weathered pebble, likely chert or fine-grained quartzite
Scientific name: Microcrystalline quartz (SiO₂), probable chert; quartzite is an alternative
Category: sedimentary
Identified: September 9, 2026
Method: Standard

AI Estimated Value

Typically $0–$5 as an ordinary collected pebble; up to about $10–$20 if unusually attractive, patterned, or demonstrably collectible.

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 as silica-rich sediment that lithified and was later rounded by stream or glacial transport; if quartzite, it began as sandstone and recrystallized during metamorphism. Exact age and source cannot be determined visually.

Uses & applications

Common chert is used historically for tools and occasionally as aggregate; quartzite is used as durable construction stone and decorative rock. This small specimen has minimal commercial value.

Geological facts

The pale, rough patches may be quartz veins, weathering, or adhering sediment. A fresh broken surface and hardness testing would distinguish chert from softer sedimentary pebbles.

Field identification & locations

Test whether it scratches glass and resists a steel knife; inspect a fresh fracture for glassy, shell-like conchoidal breakage. Chert occurs widely in sedimentary terrains, while quartzite commonly occurs in metamorphic belts and glacial gravels.