fossil

Polished fossil coral (likely fossilized honeycomb or tabulate coral)

Fossilized tabulate coral; commonly Favosites or related genera, preserved mainly as calcite (CaCO₃)

AI-generated identification · may be incorrect

Dark gray to black, polished, with tightly packed polygonal corallite chambers in a honeycomb pattern; calcite hardness 3, vitreous to waxy luster, generally no visible cleavage, and moderate specific gravity (~2.7).

Identified August 15, 2026More fossil →

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At a glance

Common name: Polished fossil coral (likely fossilized honeycomb or tabulate coral)
Scientific name: Fossilized tabulate coral; commonly Favosites or related genera, preserved mainly as calcite (CaCO₃)
Category: fossil
Identified: August 15, 2026
Method: Standard

AI Estimated Value

About $10–$40 for a common polished cabochon; $50–$150 for larger, exceptionally patterned, or provenance-rich specimens.

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 colonial marine coral fossil later mineralized during burial, commonly by calcite replacement or infilling; tabulate corals flourished mainly from the Ordovician through Permian, roughly 485–252 million years ago.

Uses & applications

Used as a cabochon, ornamental stone, fossil specimen, and educational material; not generally used in construction because it is small and decorative.

Geological facts

The repeating hexagonal pattern represents individual coral tubes, not crystal grains. Polishing accentuates the fossil structure and may darken or enhance contrast through treatment.

Field identification & locations

Identify by the regular honeycomb of tube-like cells, unlike agate or ordinary limestone; common in Paleozoic marine limestones worldwide, especially North America, Europe, and Australia. Avoid strong acids, which dissolve calcite.