fossil

Fossil Coral

Scleractinia (Fossilized Hexacoral)

Hardness: 3-4 (calcite/aragonite replacement, sometimes harder if silicified to quartz 7). Color: Brown, gray, tan, or white. Luster: Dull to vitreous. Structure: Crystalline or microcrystalline replacement of original skeletal structures.

Color: Brown, gray, tan, or white
Luster: Dull to vitreous

Identified August 6, 2026More fossil →

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Physical properties

Formation & geological history

Formed in ancient shallow marine environments where coral reefs grew, died, and were subsequently buried under sediment. Over millions of years, the original skeletal material (aragonite) was replaced by minerals such as calcite, silica, or chalcedony via permineralization.

Uses & applications

Used in lapidary arts for cabochons and decorative carvings, as well as valued specimens for fossil and mineral collectors.

Geological facts

Fossil corals can range in age from hundreds of thousands to over 400 million years old, helping geologists reconstruct ancient marine climates and geography.

Field identification & locations

Can be identified in the field by the distinct honeycomb, star-like, or tube-like coralite patterns visible on the surface. Commonly found in sedimentary limestone deposits worldwide.