Mabe pearls

Definition

A cultured pearl that has perforated the mantle of the mollusk and has naturally adhered, through layers of nacreous or non nacreous secretions applied by the mollusk, to the inner wall of the shell. The subsequently formed layers of nacreous or non nacreous material are continuous with those of the inner wall of the shell. They are round or irregular in shape and the base of the blister cultured pearl may be worked.

And the modern type of cultured blister pearl known as a Mabe pearl is produced by inserting a dome-shaped nucleus of mother of pearl, steatite or plastic between the mantle and the shell of the mollusk.

Current and Historic

The shells of Pteria penguin can reach a length of up to 25cm; they have a distinct, wing-like extension on one side and are called “Mabe gai” in Japanese. The word “Mabe” has lead to the name “Mabe pearl”, which is used by the trade, but should always be declared and explained in detail to the public and the consumers.

The Mabe pearl market began to lose interest in the pearls after World War II, but they were still found regularly on the market until into the nineteen seventies and they are sometimes even seen today. The Japanese name for this type of blister pearls from Pinctada martensii is “Hankei”.

The Culturing Process and Further Working

The rather muscular inner soft body of Pteria penguin limits the production of cultured blister pearls. A rounded or halp-spherical nucleus is glued onto the inside of each shell (which means that two pearls can be produced in one animal). The nucleus is sometimes less rounded than a half-sphere and sometimes more rounded, in which case it may take the shape of a three-quarter sphere. The color and appearance of the future pearl depend on the position of the nucleus inside of the shell, which must be sufficiently far away from the black outer rim but must not disturb the inner soft body.

The growth period amounts to two years, although it was three years in the beginning. The growth rate is low, only 0.7mm to 1.5mm per year, and varies with the season.

After the dome has been covered by a suitable thickness of nacre, the whole is cut from the shell. The dome itself is removed: steatite is used in particular for its non-adherent qualities. Then the hollow nacre shape may be filled with a resin and the base then covered by a polished mother of pearl backing piece. The diagram shows one typical shape for the backing; many composite pearls have flattened or slightly domed backs. Mabe pearls range from 9mm to 17mm or more and hear and drop shapes are commonly produced.

Market situation

Prices for Mabe pearls were stable on the international market at the end of the nineteen nineties although sales had dropped to some extent.

Generally speaking, Mabe pearls still represent a reasonable alternative to fully round pearls of the same size. While the average price for a Mabe pearl is in the range of below one hundred to a few hundred US dollars, certain colors and shapes command high prices.

The attraction of Mabe pearls lies in their size and their smooth, even surface. In addition, there are different colors and shapes which can be used perfectly for imaginative pieces of jewelry. America is still one of the best market, but the pearls sell also well in southern countries like Spain and Italy.

Maintains

Mabe pearls have to be handled with care, the thin outer nacreous layer cracks easily or gets damaged or simply separated from the filling underneath and can be removed like a hat. Cheaper qualities are more easily damaged than better ones.