QUEEN OF GEMS FROM THE OYSTER

Taupo Times, Volume XIV, Issue 43, 3 June 1965, Page 3

QUEEN OF GEMS FROM

THE OYSTER

If the diamond is the king of precious stones, then the pearl can be called their queen. Its deiicate colour and mysterious lustre have captured the hearts of women throughout the world, writes a Japanese correspondent.

Pearls were originally obtained only in their natural state in pearl oysters living in the sea. There had been various theories concerning how the pearl is formed, but today it has become clear that the pearl is formed when foreign matter accidentally gets into the oyster and the oyster, in order to protect itself from the intruder, secretes nacre around it and seals it off.

The only shells which produce genuine pearls are the pearl oyster, the white-and-black lip oyster and a few others. The first man in Japan to sueceed in cultivating pearls was the late Kokiehi Mikimoto, who was commonly known as the "Pearl King." His flrst produets were hemispherical pearls which were attached to the shell. NOT SUITABLE In July, 1893, five years

after Mikimoto first began studying methods of cultivating pearls, he discovered several semispherical pearls in the type of pearl oyster called Akoyagai. However, the produets were all semiround pearls and were not suitable for adornment. Therefore, it was necessary to round out the flat part oi the pearl by joining it with — — —— — — ■—

a piece of pearl shell of another semispherical pearl. FLOURISHED With the success in producing round pearls, the cultivation of pearls has flourished in Japan, and some 24 prefectures, around the Nankai district, are now cultivating pearls. The ideal place for cultivation is a quiet sea, where the water is not too salty and the temperature of the water is from 15 to 25 degrees Centigrade. In other words, the ideal places are the small inlets and bays of islands in the southern part of Japan. The pearl cultivators now take over and insert pieces of foreign matter into the oysters. Since the foreign matter will become the core of the pearl, care must be taken in the selection of the material used, which generally is shell from ditch clams. The shell is cut into small pieces of several millimetres thick which are inserted into the body of the other oyster with a pincer. NUMEROUS COLOURS When the piece -of shell is

inserted, part of the membrane of the mantle of the living oyster is cut out and inserted together with the nucleus. This is supposed to accelerate the rate of secretion of nacre by the oyster. The oyster is then placed in a basket and hung under a raft, and in a year, small eultured pearls are available. It takes from two to three years to produce mediumsized pearls and from five to six years for large-sized pearls. However, not all of the oysters will survive. Because of the "red current" and other damaging parasites which afiflict the oyster. only about 4,000 out of 10,000 oysters will manage to survive and produce pearls. Of the pearls produced by the 4,000 oysters, only about 10 to 15 per cent. are commercially marketable. The size of pearls pro-

duced in Japan is generally from two to three millimetres in diameter with a maximum of 10 millimetres. It is considered difficult to cultivate pearls of more than 12 millimetres as the size of the mother oyster is limited. There are numerous colours ranging from white and silver to pink, cream, black and blue. Pink and white pearls are popular in Japan and Western countries. , Pearls of different colours are produced not only because of the individual difference of the nacre excreted by the oysters but also due to the type of sea water the oyster had been placed in. Japan produces about £20,000,000 worth of eultured pearls a year, last year's exports amounting to £17,000,000.