fossil

Fossiliferous limestone, possibly an oyster or other bivalve fossil

Calcite (CaCO₃) shell material preserved in micritic limestone; exact fossil taxon cannot be confirmed from one image

AI-generated identification · may be incorrect

Gray-brown, irregular layered specimen with apparent shell growth lines and a cavity; dull to weakly earthy luster. Calcite is Mohs 3, has rhombohedral cleavage, and reacts vigorously with dilute hydrochloric acid.

Identified August 10, 2026More fossil →

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At a glance

Common name: Fossiliferous limestone, possibly an oyster or other bivalve fossil
Scientific name: Calcite (CaCO₃) shell material preserved in micritic limestone; exact fossil taxon cannot be confirmed from one image
Category: fossil
Identified: August 10, 2026
Method: Standard

AI Estimated Value

About $5–$30 for an unattributed weathered specimen; $30–$150 or more if the fossil is well preserved, identified, and locality-documented.

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 material accumulated and was buried in carbonate mud, later lithified and partly weathered or dissolved. The geological age is indeterminate without locality and diagnostic details, but such fossils range from Paleozoic to Cenozoic strata.

Uses & applications

Primarily a collecting or educational specimen; fossiliferous limestone may be used as aggregate, cement raw material, or building stone, though this piece is unsuitable for industrial use.

Geological facts

The visible ridges may represent shell growth increments, while the hollow could be a dissolved chamber or weathered cavity. A fresh broken surface and acid test would help distinguish shell calcite from ordinary limestone.

Field identification & locations

Common in marine sedimentary rocks worldwide, especially shallow-water limestone formations. Look for coherent shell symmetry, layered growth lines, and acid effervescence; avoid aggressive cleaning that could erase surface detail.