sedimentary

Weathered fossiliferous limestone

Calcitic limestone; predominantly calcium carbonate (CaCO₃), commonly containing fossil fragments

AI-generated identification · may be incorrect

Tan to brown, fine- to medium-grained, earthy and porous with irregular cavities and apparent fossil impressions or shell fragments. Calcite-rich limestone has Mohs hardness 3, vitreous-to-dull luster, no consistent crystal faces, and commonly reacts vigorously with dilute hydrochloric acid.

Identified September 2, 2026More sedimentary →

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At a glance

Common name: Weathered fossiliferous limestone
Scientific name: Calcitic limestone; predominantly calcium carbonate (CaCO₃), commonly containing fossil fragments
Category: sedimentary
Identified: September 2, 2026
Method: Standard

AI Estimated Value

Common weathered limestone: $0–$20 for loose specimens; notable fossil-bearing slabs may sell for approximately $30–$200.

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

Formed from accumulated marine carbonate mud, shells, and skeletal debris that lithified into limestone; subsequent groundwater dissolution and weathering produced the rough cavities. Exact geological age cannot be determined from the photograph.

Uses & applications

Used for aggregate, cement and lime production, building stone, and architectural facing; attractive fossiliferous pieces may be collected or displayed, but this specimen appears to be an exposed outcrop rather than gem material.

Geological facts

The dark patches may be fossil concentrations, iron/manganese staining, or soil; image resolution is insufficient for confident fossil identification.

Field identification & locations

Common in former shallow marine basins worldwide. Look for visible shell textures, low density, and strong acid fizz; distinguish it from dolostone, which reacts weakly unless powdered. Avoid collecting from protected outcrops.