Coral

Coral is not a mineral but a hard calcareous substance consisting of the continuous skeleton secreted by many tribes of marine coelenterate polyps for their support and habitation. It is found growing plant-like on the sea-bottom. With pollution on the rise everywhere it is becoming increasingly rare, to the extent that even the most prized, the Mediterranean coral, is threatened with extinction.

Coral was very popular until a few years ago, but has now become too expensive for most pockets. Its increasing rarity does. however, make it a good long-term investment. You would be wise to buy Italian coral rather than specimens from the Far East, which have often been adulterated.

The best corals are generally considered to be those of a deep rose red colour, though some jewelers would tend to disagree. Understandably so, when it is almost impossible to find more than one or two necklaces of this shade in a hundred ! As regards white and pink varieties, choose without hesitation the colour known as "angel's skin".

Weight-wise, coral is worth more on today's market than gold, which is why it is such a sound investment provided, and I stress this, it is of the best quality. The finest specimens come from Sardinia and Tunisia; larger, less fine ones from Japan and China.

Coral is cut en cabochon or used for beads and sometimes small carvings. Beware of imitations, such as coloured shell or bone.