sedimentary

Weathered fossiliferous limestone

Calcitic limestone, predominantly calcium carbonate (CaCO₃), possibly bioclastic limestone

AI-generated identification · may be incorrect

Typically light tan to gray, earthy to dull luster, hardness about 3 Mohs, and irregular fracture; visible cavities and dark fossil fragments suggest dissolved shells or skeletal material in a calcite-rich matrix. It reacts vigorously with dilute hydrochloric acid or vinegar if fresh surfaces expose calcite.

Identified August 23, 2026More sedimentary →

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At a glance

Common name: Weathered fossiliferous limestone
Scientific name: Calcitic limestone, predominantly calcium carbonate (CaCO₃), possibly bioclastic limestone
Category: sedimentary
Identified: August 23, 2026
Method: Standard

AI Estimated Value

About $5–$25 for a common loose specimen; $25–$100 or more if fossils are clearly identifiable, attractive, and legally collected.

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 when marine shell, coral, or other skeletal debris accumulated and lithified in shallow-water carbonate environments; age cannot be determined from the photograph and may range from Paleozoic to Cenozoic. Weathering and groundwater dissolution produced the porous, irregular surface.

Uses & applications

Used as crushed aggregate, road base, cement and lime feedstock, building stone, and occasionally decorative material; fossiliferous pieces are collected as geological specimens. This rough, weathered example has limited commercial value.

Geological facts

The specimen appears to contain fossil molds or shell fragments, but image resolution prevents reliable identification of the organisms. Dark spots may also include iron/manganese staining or noncarbonate rock fragments.

Field identification & locations

Look for shell patterns, rounded fossil cross-sections, layered carbonate texture, and acid effervescence; common sources include former marine platforms worldwide. Avoid relying on color alone, and test an inconspicuous fresh surface.