Agatized Coral

Agatized coral, Florida’s state stone, is a rare fossilized coral found in North Florida, mainly along the Suwannee River. Formed 20-30 million years ago, it features colorful patterns created by chalcedony, quartz, or opal replacing the original coral structure.

Agatized coral is the fossilized remains of ancient coral, typically from the Paleocene to Miocene epochs, which lived in shallow marine environments tens of millions of years ago. Over time, the coral's original calcium carbonate skeleton is gradually replaced by chalcedony, a microcrystalline form of quartz (SiO₂), through a process called silicification or agatization.