fossil

Fossil Coral

Rugosa or Tabulata coral fossil

Mohs hardness around 3 to 4, typically gray, brown, or tan in color, dull to vitreous luster when polished, calcite or quartz composition, specific gravity around 2.6 to 2.7.

Identified July 29, 2026More fossil →

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Physical properties

Mohs hardness around 3 to 4, typically gray, brown, or tan in color, dull to vitreous luster when polished, calcite or quartz composition, specific gravity around 2.6 to 2.7.

Formation & geological history

Formed through the process of permineralization or replacement where ancient coral skeletons, dating from the Paleozoic era (such as the Devonian or Carboniferous periods), were slowly replaced by minerals like silica or calcite over millions of years.

Uses & applications

Used primarily in lapidary work, as cabochons in jewelry, and highly sought after by fossil and rock collectors.

Geological facts

Fossil corals often preserve the intricate internal structures of ancient colonial marine organisms, providing a window into prehistoric shallow marine ecosystems that existed hundreds of millions of years ago.

Field identification & locations

Identified by its distinctive honeycomb or cellular pattern on the surface, commonly found in sedimentary limestone formations worldwide, particularly in regions with ancient shallow seas.