sedimentary

Rounded sedimentary pebble, likely limestone or calcareous sandstone

Indeterminate carbonate-rich clastic rock; possibly micritic limestone (predominantly CaCO₃)

AI-generated identification · may be incorrect

Pale gray-green, fine-grained, dull to slightly earthy luster, with a rounded water-worn form and subtle pores or specks. Likely Mohs hardness 3–4 if limestone, or 5–6 if sandstone; cleavage is absent or indistinct.

Identified September 7, 2026More sedimentary →

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At a glance

Common name: Rounded sedimentary pebble, likely limestone or calcareous sandstone
Scientific name: Indeterminate carbonate-rich clastic rock; possibly micritic limestone (predominantly CaCO₃)
Category: sedimentary
Identified: September 7, 2026
Method: Standard

AI Estimated Value

Typically $1–$10 as an ordinary collected pebble; perhaps $10–$30 with documented locality or notable fossil content.

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 formed from compacted carbonate mud or sand, then rounded by stream, beach, or glacial transport; its exact geological age and locality cannot be determined from the photograph.

Uses & applications

Common material for aggregate, road base, cement manufacture, and landscaping; this specimen has little commercial or jewelry value unless it has an unusual provenance.

Geological facts

A drop of dilute hydrochloric acid or vinegar may fizz on a limestone surface, though weak vinegar can be inconclusive. The uniformly rounded shape indicates natural abrasion rather than a crystal habit.

Field identification & locations

Look for visible grains, fossils, and acid reaction: strong fizz suggests calcite-rich limestone, while gritty texture and no reaction favor sandstone. Common worldwide in sedimentary terrains, riverbeds, beaches, and glacial deposits.