Coral reefs are actually the skeletal remains of millions of coral polyps and are now considered endangered ecosystems. As a result, Earth-conscious jewelers have turned to apple coral, a non-endangered species of coral.
Apple coral is part of the species of corals known as melithaea sponge, which is commonly found on the ocean floors around the waters of Taiwan, Indonesia and southern China.
Apple coral is also known as red coral, tiger coral, limestone, red stone and coral sea fan.
Apple coral that has been shaped into beads, then sealed and polished, is usually a deep reddish color. When the apple coral is exposed to heat or intense sunlight for long periods, it tends to lighten.
The destruction of coral reefs around the world led to a global ban on coral mining and collecting in 1992, but apple coral was not included. The United States has placed a ban on shipping coral in and out of the country, but there is no ban on the melithaea sponge corals.
Apple coral is often mistaken for Mediterranean coral, which is no longer used in fine-jewelry making. Because there is virtually no Mediterranean coral left to excavate, any that is set in jewelry today has been most likely taken from an older piece.