Coral was so widely accepted for its power to cure madness, safe-passage the hero traveler or control the climate that is was periodically mounted in the same piece of jewelry with such titan gems as ruby, emerald and sapphire.

It was usually left in its natural shape, and not shaped or cut like other materials. Despite the relative ease with which coral is found, it was popular in the extreme and is customarily found in old or antique jewelry. For many years the modern world ignored it, turning its attention to rare, expensive types of decorations. Today there is a resurgence of interest in this simple-seeming material. Formed beneath the sea in a colony of marine-life invertebrates called ‘coral polyps', this isn't a typical kind of gem, but a skeletal calcium carbonate gem, so it very soft on the Moh scale, rating only a 3.5. The coral is the natural habitat of the polyps and they eventually grow into reefs. It is formed bit by small bit, allowing for a tree-like appearance of tiny branches each sending its shoot out to form the next ‘branch'. The main sources for coral are the Mediterranean and Red Seas , though they also come from Australia , Malaysia , the Philippines , Japan , Ireland , Taiwan and Hawaii .

Coral is either opaque or semi-translucent and comes in pretty shades of pink, cream, white (from Japan ), orange and even rarer shades of red or black (that comes from Hawaii and Mexico ). Coral today is usually cabochon cut to resemble small pink pearls or left traditionally untouched. It is vulnerable to wear and tear and should never be exposed to any type of acid (such as ordinary house-vinegar), as it is calcium-based. The most common variety of coral is angel-skin coral; a white coral that had faint bluish undertones around the spinal edges of each branch. The common types are every shade of cream or pink or orange. The most expensive kind is ‘blood coral', also called ‘oxblood' coral or ‘noble' coral. This is the rare red type and the best specimens are brought out of the sea around Italy