AKOYA CULTURED PEARLS
Cultured Pearls
The First 100 Years
MAIN CHARACTERISTICS
Because of the relatively small size of the mother oyster, which grows to only about 7cm or 8cm in diameter at maturity, these pearls are correspondingly smaller.
Generally, they range from 2mm to 9mm or, very rarely, 10mm. First cultivated in Japan, the Akoya has been the traditional cultured pearl for almost a century.
GEOGRAPHICAL ORIGINS
Until the early 1990s, Japan was the uncontested leader in Akoya pearl cultivation. Very small harvests of Akoya pearls cultured in other countries such as Korea and China had little or no influence on Japan’s dominance. But in the early 1990s, China started to produce large volumes which now pose a serious threat to the traditional Japanese Akoya pearl industry. This situation has been compounded by Japan’s high costs and the serious pollution of its sea water.
OYSTERS
Akoya pearls are cultivated in a bivalve mollusc of the family Pteriidae, the genus Pinctada, the species fucata, and the sub-species martensii, giving the shell its scientific name Pinctadafucata martensii. For common usage, it is more simply referred to as the “Akoya shell”
According to a recent book by Dr Shohei Shirai entitled “Pearls and Pearl Oysters of the World’ the Akoya shell is more accurately defined as Pinctada imbricata. It includes the species Pinctada fucata, Pinctada vulgaris, Pinctada radiata, and the species (or sub-species) martensii. It is found not only in Japan, Korea and China, but practically throughout East Asia, the Indo-Pacific area, the Red Sea, the Persian Gulf, the Mediterranean Sea, around South Africa and in the Caribbean.
The Akoya shell without a pearl inside is of little value, mainly because of its thinness and small size. The methods now used to obtain Akoya pearl oysters are by spat collection and by breeding. These methods have replaced the traditional Ama divers who were active in Japan until the early 1960s. Ama can still be seen occasionally in exhibitions and are fondly remembered as romantic symbols of the early days of pearl cultivation in Japan
CULTIVATION
As with South Sea pearls, a spherical mother-of-pearl nucleus, together with a tiny sliver of mantle tissue, is carefully implanted into the host oyster. However, the resemblance stops there.
With the Akoya, one, two and sometimes even three or four nuclei can be inserted at the same time into a single oyster, depending on the size and health of the shell and the size of the nuclei. With South Sea pearls, only one nucleus is inserted. Another major difference is the cultivation time; Akoyas get a lot less time in the sea. The resulting layer of nacre around the nuclei of an Akoya pearl is correspondingly thinner. Still another difference is that, after harvesting their pearls, Akoya oysters are not re-seeded.
COLOURS
In discussing Akoya pearl colours, one must, however reluctantly, accept the fact that they are enhanced by man. A harvest of Akoya pearls in its raw and unprocessed stage is mainly cream, yellow and green; the Akoya pearls in the shop windows are mainly white, silver, pink and champagne. This is mainly the result of a process during which impurities are bleached out. The pearls are also given lighter and more popular tints which makes their colours more homogeneous
SHAPES
On average, the percentage of round and near-round pearls in a harvest of Akoya pearls is substantially higher than in a harvest of South Sea pearls. But there are still all kinds of shapes including oval, button, drop and baroque that can be found.
Because very often more than one nucleus is inserted into an Akoya shell, twin pearls are sometimes harvested. This happens when two closely placed nuclei start to grow together during the cultivation period forming a “Siamese twin pearl.”
VALUE
As with other pearls, the price is based on availability, size and quality which would include shape, colour, lustre, and the cleanliness and texture of the surface. For probably less than one hundred dollars, a decent pair of earrings can be purchased, and for not much more, a very decent necklace of small-size pearls (originating most likely in China). On the opposite side of the price spectrum, an extremely fine strand of 8mm or 9mm Japanese Akoya pearls can cost several thousand dollars.
RECOMMENDATIONS
Avoid Akoya cultured pearls with a relatively thin layer of nacreous coating over the implanted nucleus. They will eventually lose some of their lustre, and might even change colour as time passes. It is therefore of the utmost importance to verify the thickness and health of the coating. A visual and tactile examination will let you judge size, shape, colour, lustre and surface. But evaluating the thickness of the coating should be left to a trusted expert.
A good-quality Akoya pearl need not be silver-pink, round and clean. But it should have a thick coating and fair to very good lustre. Akoya pearls that are off-round or baroque often have good coatings and lustre. They thus represent excellent value for the money.
As with South Sea pearls, chose the colour that appeals to you, that is you. If a pearl necklace is long, or to be worn over clothing, or if the wearer does not have an extremely fair complexion, cultured pearls with slightly creamy, champagne or greenish undertones are recommended. After wearing such pearls for a time, many people actually start to prefer them over all others because of the unique warmth and charm they possess. And once again, tolerance is the key when judging the cleanliness of the surface. Tiny spots and minor impurities are usually not the shortcomings of man but the handiwork of nature.
Thank you,
Andy Muller for permission to reproduce this Piece
Cultured Pearls
The First 100 Years
