Rock Identifier
Fossil Coral (Rugosa or Tabulata coral fossil (Calcium Carbonate, CaCO3)) — fossil
fossil

Fossil Coral

Rugosa or Tabulata coral fossil (Calcium Carbonate, CaCO3)

AI-generated identification · may be incorrect

Hardness: 3-4 on the Mohs scale. Color: White, gray, or tan. Luster: Dull to vitreous. Crystal structure: Trigonal (calcite replacement).

Hardness
3-4 on the Mohs scale
Color
White, gray, or tan
Luster
Dull to vitreous
Identified More fossil →
Explore Fossil Coral in the encyclopedia →

Identify your own rocks.

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

App StoreGoogle Play

Physical properties

Hardness: 3-4 on the Mohs scale. Color: White, gray, or tan. Luster: Dull to vitreous. Crystal structure: Trigonal (calcite replacement).

Formation & geological history

Formed when ancient coral skeletons were buried in marine sediments and replaced by minerals over millions of years.

Uses & applications

Used in lapidary arts, decorative cabochons, jewelry, and educational or fossil collecting.

Geological facts

Many fossil corals are preserved as agate or chalcedony replacements, making them durable enough for polishing. They provide vital clues about ancient marine ecosystems.

Field identification & locations

Identified by distinct honeycomb or star-shaped cellular patterns left by coral polyps. Found globally in ancient limestone deposits.

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