fossil

Fossiliferous limestone, possibly coral or stromatoporoid fossil

Calcitic limestone; predominantly CaCO₃, with fossilized colonial-organism structures

AI-generated identification · may be incorrect

Gray, cream, and yellow-brown, fine-grained to crystalline, with rounded layered/colonial patterns and dull to waxy luster. Calcite has Mohs hardness 3, rhombohedral cleavage, and specific gravity about 2.7; it should fizz with dilute hydrochloric acid or strong vinegar if calcitic.

Identified August 8, 2026More fossil →

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At a glance

Common name: Fossiliferous limestone, possibly coral or stromatoporoid fossil
Scientific name: Calcitic limestone; predominantly CaCO₃, with fossilized colonial-organism structures
Category: fossil
Identified: August 8, 2026
Method: Standard

AI Estimated Value

About $10–$50 for a common specimen; $75–$200+ if the fossil identity, locality, preservation, or preparation is exceptional.

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

A marine carbonate deposit later lithified and partly recrystallized, preserving concentric or honeycomb-like fossil structures. The exact geologic age cannot be determined from the photograph; similar specimens range from Paleozoic to Mesozoic.

Uses & applications

Used mainly as a teaching, display, and collecting specimen; limestone may be quarried for cement, aggregate, and building stone, but this piece is primarily decorative.

Geological facts

The central and surrounding curved bands resemble a colonial reef organism such as coral or stromatoporoid, though a polished or weathered limestone texture can look similar.

Field identification & locations

Look for consistent biological patterns, calcite reaction, and absence of glassy luster; a hand lens can reveal tiny corallites or cells. Common in ancient marine limestone regions worldwide.