sedimentary

Quartz-rich pebble, possibly chert or silicified limestone

Microcrystalline quartz (SiO₂), possibly chalcedony; exact identification is uncertain from the photograph

AI-generated identification · may be incorrect

Small rounded, pale cream-gray specimen with a dull to slightly waxy luster and white curved bands or veins. Likely hardness about 6.5–7 if quartz-rich; cleavage absent, fracture commonly conchoidal; moderate density around 2.6 g/cm³.

Identified August 11, 2026More sedimentary →

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At a glance

Common name: Quartz-rich pebble, possibly chert or silicified limestone
Scientific name: Microcrystalline quartz (SiO₂), possibly chalcedony; exact identification is uncertain from the photograph
Category: sedimentary
Identified: August 11, 2026
Method: Standard

AI Estimated Value

Usually $1–$10 as an ordinary pebble; approximately $10–$30 if the banding proves attractive and it polishes well.

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 weathered river or soil pebble formed by silica cementation, replacement, or chalcedony deposition in sedimentary rocks. The regional setting near 17.2°N, 89.1°W (Petén, Guatemala) commonly exposes limestone and alluvial sediments, making silicified limestone or chert plausible.

Uses & applications

Primarily a curiosity or lapidary material; suitable for tumbling or small cabochons if it cuts cleanly. Not generally used commercially unless present in large deposits.

Geological facts

The pale curved markings may be chalcedony bands, fossil/replacement textures, or weathering surfaces rather than true layering. A steel file should not scratch quartz-rich material, while a knife may scratch softer limestone.

Field identification & locations

Field tests are useful: quartz-rich material scratches glass and does not fizz in dilute hydrochloric acid; calcite-rich limestone fizzes strongly and is softer. Commonly found as stream cobbles and weathered residual fragments in limestone terrains.