The Creation of a Pearl

PEARLS are balls of calcium carbonate, created in the form of lustrous nacre around a nucleus which is irritating an oyster.

The nucleus may be natural, a bit of grit or shell, or may be a bead of Mississippi pig-toe mussel shell implanted to create an artificially large pearl.

In modern pearl production, the results are cultured round pearls, cultured irregularly shaped pearls (baroque), half-round pearls (mabe) made by fixing hollow plastic shapes to the oyster's shell wall in its last year of production, and irregularly-shaped natural pearls with no artificial nucleus (keshi or seedless pearls).

Photo : Jiri Lochman Seeding a Pearl Oyster

Many of the terms used are Japanese (keshi means 'poppyseed') and the major unit of measurement in pearl production is a 'kan', equivalent to 3.75 kg.

Most of Australia's South Sea pearls come from Broome's P. maxima oysters. These pearls are the largest and finest in the world, with their silvery whiteness or overtones of rose, blue or gold.

The best pearls come from contented oysters, and the operations of pearl farms are designed to minimise stress on them, moving them while tides and temperatures are fairly stable, cleaning them of marine parasites, and hanging them from panels in the water column to keep them flushed with nutrients and carry waste away.

But it's a lot of work, much of it labour intensive, as can be seen from the following pearl farm's working calender.

Maxima Pearls is a medium-sized company, with a farm in the remote and beautiful turquoise waters of Cone Bay and their work schedule is fairly typical for a pearl farm in this region.

Tending the oysters is a continuous process aimed at keeping pearls developing smoothly to minimise blemishes caused by stress.

Every healthy oyster has a helper, a tiny pea-crab which lives unharmed within, sharing debris which the oyster sucks in and probably keeping it clean. The fate of the crab once the oyster dies is a mystery, but its presence seems essential for the oyster's well-being and seeders are careful not to harm it.

Most of the technicians who seed the oysters are Japanese, but some Australians are in training, and they travel the world working six to eight week stints at each farm.

Producers expect four year's production from a good oyster, seeding it first at about two years old, and in its last year it will be used for mabe (half-shell) production.

However, once a nucleus, plus a small piece of mantle tissue from another oyster has been successfully placed in a small pouch cut in the gonad, two years must pass before the pearlers know what sort of pearl they have.

Theoretically, the longer a pearl has to develop, the thicker and deeper the coating of nacre and the higher quality of the pearl. But there is a limit to what is practical, according to Russel Hanigan, Broome manager of pearl producer, Paspaley Pearling.

"Any pearl producer can produce a huge pearl if they wanted to," Mr Hannigan said.

"You can set aside 1000 shells, leave them there for an extra year and you could make a really big pearl, 21 mm diameter if you really wanted to, but so what?"

'show me what it looks like inside, show me the skin on it. If it's a really good skin then it's probably worth more than any 21 mm pearl to date, but what can you do with a 21 mm pearl? Play golf?"

Producers aim for smooth round cultured pearls, although the quirks of the keshi and baroque pearls offer jewellers most scope.

The closer to the equator, the duller the pearls seem to become, and Indonesian farms using P.Maxima are producing so-called 'ivory pearls', which are yellowish and lack lustre.

Nothing is wasted, with excellent prices paid for both oyster meat (in Australia and Hong Kong) and the glorious P. Maxima mother of pearl shell, sent to the US, Japan, SE Asia, France and the Middle East for buttons and inlay work.