Florida: agatized coral (state stone)
Florida: agatized coral (state stone)
Florida does not yet recognize a state fossil, but its state stone, agatized coral, is actually a fossil. Agatized coral can be any of many species of corals which have been replaced by agate, a variety of quartz chalcedony. It takes a very long time to form, and most of the agatized coral found today in the state lived in the vast Eocene seas which covered the state 35-40 million years ago, when Florida was part of the continental shelf.
Coral reefs are familiar to most of us today. Reefs have been around since the early Paleozoic Era, but the types of corals then were very different. Early reefs were composed of tabulate and rugose corals, which went extinct at the end of the Permian, around 245 million years ago. After that, modern scleractinian corals arose and filled the reef niche.
What collectors find is actually just the skeleton of the coral, initially composed of calcium carbonate. Living corals are composed of individual polyp animals which live colonially in these massive skeletons. The animals harbor symbiotic algae, called zooxanthellae, within their tissues, giving them a variety of colors. Agatized corals may also have a variety of colors, but in this case it is trace minerals within the agate that impart the hues.
The Florida Legislature designated agatized coral as the state stone in 1979.
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