Rock Identifier
Porous fossil coral fragment (Fossilized colonial coral; precise taxon cannot be determined from the image) — fossil
fossil

Porous fossil coral fragment

Fossilized colonial coral; precise taxon cannot be determined from the image

AI-generated identification · may be incorrect

Cream-colored, highly porous, irregular branching form with small circular corallite-like pits. Likely calcite or aragonite; Mohs hardness about 3–4, with a dull to slightly waxy luster. Crystal structure is not identifiable visually.

Identified More fossil →
Explore Porous fossil coral fragment in the encyclopedia →

Identify your own rocks.

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

App StoreGoogle Play

Physical properties

Cream-colored, highly porous, irregular branching form with small circular corallite-like pits. Likely calcite or aragonite; Mohs hardness about 3–4, with a dull to slightly waxy luster. Crystal structure is not identifiable visually.

Formation & geological history

Coral skeletons accumulated in warm, shallow marine settings and were later preserved by mineralization, commonly as calcite. The specimen’s age and exact formation cannot be determined from the photo.

Uses & applications

Primarily collected or displayed as a natural-history specimen; fossil coral is also used decoratively and occasionally in jewelry.

Geological facts

The repeated tiny pits may be coral corallites, but porous carbonate rock and other fossils can look similar.

Field identification & locations

Check for repeated, organized corallite patterns and a carbonate reaction to dilute acid; avoid acid-testing valuable specimens. Fossil corals occur in marine sedimentary rocks worldwide.

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
Fossil oyster shell (Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)) — fossil

Fossil oyster shell

Oyster (family Ostreidae); shell composed chiefly of calcite (CaCO₃)

fossil
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