fossil

Fossilized Coral

Cnidaria (Hexacorallia)

Mohs hardness around 3-4 (if calcified), or 7 (if completely silicified/agateized); color is typically white, grey, or tan; dull to waxy luster; amorphous or cryptocrystalline structure.

Identified July 29, 2026More fossil →

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Physical properties

Mohs hardness around 3-4 (if calcified), or 7 (if completely silicified/agateized); color is typically white, grey, or tan; dull to waxy luster; amorphous or cryptocrystalline structure.

Formation & geological history

Formed from ancient coral reefs where the original skeletal material (calcium carbonate) was preserved and often replaced by minerals like silica or calcite over millions of years.

Uses & applications

Used in lapidary arts, ornamental carvings, jewelry, and as educational or display specimens for fossil collectors.

Geological facts

Fossil coral often shows intricate patterns of the coral polyps, making each specimen unique. Some fossil corals are replaced by agate, turning them into precious gemstones.

Field identification & locations

Found worldwide in sedimentary rock formations that were once shallow ancient seas. Look for distinctive star-shaped or honeycomb patterns on the weathered surface.