Rock Identifier
Fossilized coral or stromatoporoid fragment (Likely tabulate coral (order Tabulata) or stromatoporoid; exact identification requires microscopy) — fossil
fossil

Fossilized coral or stromatoporoid fragment

Likely tabulate coral (order Tabulata) or stromatoporoid; exact identification requires microscopy

AI-generated identification · may be incorrect

Cream-to-brown silicified or calcitic material with distinctive concentric, wavy growth bands and a dull to slightly waxy luster; hardness approximately 3–7 depending on calcite versus silica, with no obvious cleavage. The texture is organic and laminated rather than crystalline.

Identified More fossil →
Explore Fossilized coral or stromatoporoid fragment in the encyclopedia →

Identify your own rocks.

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

App StoreGoogle Play

Physical properties

Cream-to-brown silicified or calcitic material with distinctive concentric, wavy growth bands and a dull to slightly waxy luster; hardness approximately 3–7 depending on calcite versus silica, with no obvious cleavage. The texture is organic and laminated rather than crystalline.

Formation & geological history

A colonial marine organism formed successive skeletal layers on an ancient seafloor, later buried and mineralized. Similar fossils commonly range from Ordovician to Devonian age (about 485–359 million years old), though age cannot be determined from the image.

Uses & applications

Primarily a collecting, educational, or decorative specimen; polished fossil coral is sometimes used in jewelry and cabochons. It has little industrial value as an isolated fragment.

Geological facts

The swirling bands record repeated biological growth and resemble tree rings, but they formed underwater. Fossil corals are important indicators of ancient shallow, warm marine environments.

Field identification & locations

Look for repeated corallite pores, honeycomb texture, or layered internal walls on a freshly broken or magnified surface; a hand lens is useful. Common in Paleozoic limestone deposits worldwide, including North America, Europe, and Australia.

More like this

Other fossil specimens

Probable fossil-bearing rock or mineral concretion (Unidentified carbonate-rich concretion with a possible fossil inclusion) — fossil

Probable fossil-bearing rock or mineral concretion

Unidentified carbonate-rich concretion with a possible fossil inclusion

fossil
Likely fossil oyster shell (Fossilized bivalve shell; exact species cannot be identified from the image) — fossil

Likely fossil oyster shell

Fossilized bivalve shell; exact species cannot be identified from the image

fossil
Crinoid Stem Fossil in Matrix (Phylum Echinodermata, Class Crinoidea) — fossil

Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

fossil
Fossiliferous limestone (likely a crinoidal or shell-fragment limestone) (Bioclastic limestone, composed chiefly of calcite (CaCO₃)) — sedimentary

Fossiliferous limestone (likely a crinoidal or shell-fragment limestone)

Bioclastic limestone, composed chiefly of calcite (CaCO₃)

sedimentary
Porous limestone pebble (Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image) — sedimentary

Porous limestone pebble

Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image

sedimentary
Weathered fossil bone fragment (identification uncertain) (Fossilized bone; exact taxon and mineral composition cannot be determined from the image) — fossil

Weathered fossil bone fragment (identification uncertain)

Fossilized bone; exact taxon and mineral composition cannot be determined from the image

fossil