Fossil coral was once the skeleton of a coral polyps whose organic structure has been transformed to stone. After the coral died, the skeleton became saturated with water that contained dissolved silica, the same mineral that is the principal component of quartz, chalcedony, agate, and jasper. In this case, the silica replaced the coral’s soft tissues and filled its cavities. Because the skeleton was encased in silica, oxygen couldn’t get to it, and it didn’t completely deteriorate. You can still see the traces of its structure in the fossilized gem. The different colors that you see in fossil coral come from the different minerals that existed in the silica solutions, which usually harden into a chalcedony or agate. (For a list of physical characteristics, please see Agate.)
Fossil coral is also known as agatized coral, Indonesian coral, and Indonesian jasper.
Fossil corals are found throughout the world in sedimentary rocks. Many of these corals originally lived between 215 and 340 million years ago. In the United States, fossil coral has been found in Kansas, Pennyslvania, Kentucky, and West Virginia where it has been named the State Gemstone. It’s also found in Indonesia.
Fossil coral comes in a range of gentle colors: tans, greys, pinks, yellows, browns, and occasionally red. There’s also a fair amount of variety in the pattern which can range from a banded effect that almost looks as if it’s been painted on with watercolors to the distinctive flower and starburst patterns.

Fossil coral beads, being chalcedony, are fairly tough, with a hardness of 7, so you can safely bead them into any sort of jewelry. Our fossil coral beads come in beautiful shades of browns and pinks and greys, and will look lovely when combined with smoky quartz and ametrine. For contrast, try beading them with the green or grey or even red jaspers.