fossil

Coral Fossil (or Tumbled Shell/Coral fragment)

Anthozoa (Fossilized Coral)

White to off-white, opaque, often shows pores, septa, or a star-like pattern if a cross-section of a corallite. Hardness varies (3.5-4 if primarily calcite or aragonite, up to 7 if silicified). Usually has a dull to waxy luster when tumbled.

Identified July 31, 2026More fossil →

Explore Coral Fossil (or Tumbled Shell/Coral fragment) in the encyclopedia →

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Physical properties

Formation & geological history

Formed in marine environments as the calcareous exoskeletons of coral polyps. Can range in age from Ordovician to recent. Often found on beaches where it has been naturally tumbled by wave action.

Uses & applications

Collected for aesthetic value, often used in crafts or inexpensive jewelry, sometimes tumbled and polished.

Geological facts

Fossil corals are often found washed up on beaches. In some areas, silicified versions (like Petoskey stone, which is a type of rugose coral) are highly prized.

Field identification & locations

Identify by its intricate, repeating patterns (such as tiny stars, pores, or septal ridges) which distinguish it from plain limestone or quartz pebbles. Commonly found along coastlines or in ancient seabed deposits.

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Crinoid Stem Fossil in Matrix

Phylum Echinodermata, Class Crinoidea

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Sedimentary Outcrop (Sandstone/Shale)

Sedimentary bedrock formation (variable composition)

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Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

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Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

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Fossiliferous Limestone

Limestone with embedded fossil cross-section

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Fossiliferous Limestone with Crinoid stems

Limestone (CaCO3) containing Crinoidea fossils

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