Coral is a product of sea. It is formed from the calcareous skeletons of myriads of tiny polyps (which means insect with many feet) which live in vast colonies in warm waters at a moderate depth. It is composed chiefly of calcium carbonate. This is arranged as fibres radiating from the central axis of the curving coral branches. Its specific Gravity is 2.68 and hardness is less than 4 on the Moh’s scale. It is an opaque stone. Many forms of coral exist but only high quality Red, Pink, Blue, Black and white corals are used in jewellery.
Corals are found in India, Italy, Australia, Sri Lanka, Japan, Malasia, South, Africa, Algeria and U.S.A.
Coral, being an opaque gem, is very difficult to identify. A lot of eye practice is required to differentiate between a natural and a manmade coral. Natural corals, if seen under magnification, always tell the story of their origin. They have black marks which are actually holes.
A very careful examination is required to identify a natural coral. As real corals are not very clear and if clear they are very costly. Manmade corals are very commonly found in the market places being sold as real corals.