fossil

Fossiliferous limestone, possibly coral limestone

Calcite-rich carbonate rock; chiefly calcium carbonate (CaCO₃), with probable fossil coral or shell structures

AI-generated identification · may be incorrect

Typically gray to cream, dull to weakly pearly, porous, and relatively soft (Mohs 3); calcite may show rhombohedral cleavage, and dilute hydrochloric acid causes vigorous fizzing. The rounded cavities and cellular patterns suggest recrystallized fossil coral or other skeletal carbonate material.

Identified September 6, 2026More fossil →

Explore Fossiliferous limestone, possibly coral limestone in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Fossiliferous limestone, possibly coral limestone
Scientific name: Calcite-rich carbonate rock; chiefly calcium carbonate (CaCO₃), with probable fossil coral or shell structures
Category: fossil
Identified: September 6, 2026
Method: Standard

AI Estimated Value

Common rough specimens: $5–$30; distinctive, well-preserved fossil coral pieces: roughly $30–$150.

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 skeletal debris and carbonate mud, later lithified and partly dissolved or recrystallized; age cannot be determined from the photograph and may range from Paleozoic to Cenozoic depending on locality.

Uses & applications

Used as aggregate, cement and agricultural lime; attractive fossiliferous pieces are collected, displayed, or cut for decorative stone, though this specimen appears primarily a field specimen.

Geological facts

Irregular honeycomb or coralline textures can preserve the original colony structure even after burial and mineral alteration.

Field identification & locations

Look for consistent biological cell patterns, abundant calcite, low hardness, and acid reaction; common in ancient marine limestone beds worldwide. Avoid confusing it with vesicular volcanic rock, which is harder and does not fizz in acid.