fossil

Fossil Coral

Anthozoa (Scleractinia)

Hardness: 3-4 (Calcite/Aragonite); Color: White, cream, or light tan; Luster: Dull to earthy; Structure: Hexagonal or radiating septa patterns within circular corallites; Specific gravity: Approx 2.7

Hardness: 3-4 (Calcite/Aragonite)
Color: White, cream, or light tan
Luster: Dull to earthy

Identified July 15, 2026More fossil →

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Physical properties

Hardness: 3-4 (Calcite/Aragonite); Color: White, cream, or light tan; Luster: Dull to earthy; Structure: Hexagonal or radiating septa patterns within circular corallites; Specific gravity: Approx 2.7

Formation & geological history

Biological origin; marine polyps secrete calcium carbonate skeletons which become fossilized over millions of years through lithification and mineralization. Common in limestone deposits.

Uses & applications

Home decor, aquarium aquascaping, jewelry (agatized varieties), and source of agricultural lime.

Geological facts

Coral fossils found on land, even in mountains, prove that those areas were once submerged under ancient shallow seas. Some fossil corals are 'agatized', meaning they have been replaced by chalcedony (quartz).

Field identification & locations

Identified by recurring geometric floral or honeycomb-like patterns. Commonly found in limestone quarries, riverbeds, and coastal regions with ancient tectonic uplift.