It is beautiful in rings, necklaces, and pendants. It is the skeletal remains of coral polyps. Red, pink, and white coral is mostly calcium carbonate. Black and golden coral is conchiolin. It has a hardness of 3.
Coral is especially fragile.
Protect coral from scratches and sharp blows. Do not clean coral in a home ultrasonic cleaner. Coral is often imitated by plastic, glass, porcelain, and stained bone. Natural coral has a distinctive wood grain texture which can help identify it as the real thing. Coral is found on the African coasts, Australia, Japan, Mediterranean coasts, Malaysia, and the West Indies.