Fossil Coral

The pattern that looks like little flowers on the stone is neither a painting nor a coincidence. Each "flower" is the skeleton of a single coral polyp, a tiny sea creature that lived in a colony with thousands of neighbors. Millions of years ago they built a reef. Today they are jewelry.

The original coral was made of calcium carbonate. Over a very long time, silica-rich groundwater seeped through it, dissolved the original material and deposited agate, a type of chalcedony, in its place. The result is a pseudomorph: one mineral that has taken the place of another while keeping its original shape, down to the small details. Its precise name is agatized coral.

According to the Florida Museum, the fossil corals in its collection lived about 34 to 28 million years ago. In 1979 the Florida Legislature made agatized coral the official state stone. Fossil coral is also found in Indonesia and elsewhere.

Because the coral has turned into agate, it is much harder than ordinary coral: 6.5 to 7 on the Mohs scale, about the same as quartz. So even though it looks delicate, you can wear it without worrying too much. Just don't try to return it to the sea. It is past that stage.