fossil

Fossil Coral / Fossilized Coral

Scleractinia (Anthodiscus / Favia / Montastraea fossil)

Hardness: 3-4 on Mohs scale (aragonite/calcite composition); Color: Off-white, grey, tan, or beige; Luster: Dull to earthy; Structure: Hexagonal or radiating corallite patterns visible in cross-section with longitudinal tube-like septa structures.

Hardness: 3-4 on Mohs scale (aragonite/calcite composition)
Color: Off-white, grey, tan, or beige
Luster: Dull to earthy

Identified July 26, 2026More fossil →

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Physical properties

Formation & geological history

Formed through the bio-mineralization of calcium carbonate by marine coral polyps in warm shallow seas, followed by burial and fossilization (permineralization or recrystallization) over thousands to millions of years.

Uses & applications

Used in educational collections, home decor, aquariums, lapidary arts, and gemstone jewelry when silicified (agate coral).

Geological facts

Fossil corals can range from recent beach specimens to ancient structures hundreds of millions of years old. Agatized corals occur when original calcium carbonate is replaced by chalcedony silica.

Field identification & locations

Identified by the distinct honeycombed or star-like pore structures (corallites) on the surface and long parallel ridges/septa along broken edges. Common along coastal regions, ancient raised reefs, and marine limestone deposits.

Other fossil specimens

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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)

sedimentary

Chert with Fossil Brachiopod

Microcrystalline Quartz (SiO2) with Calcitic Brachiopod inclusion

sedimentary

Fossilized Crinoid Stem in Limestone

Crinoidea (Class) in Calcium Carbonate (CaCO3) matrix

fossil

Fossiliferous Limestone

Limestone with embedded fossil cross-section

sedimentary

Fossiliferous Limestone

Fossiliferous Calcilutite / Biomicrite

sedimentary