South Sea Cultured Pearls
Definition
The Japanese used to term “South Sea cultured pearl” for pearls produced in marine waters south of Japan. Meanwhile, this name has become something of a synonym for large cultured pearls form Pinctada maxima or Pinctada margaritifera.
Extensively the pearl cultured in areas of the Indian and Pacific Oceans, including Myanmar, Indonesia, Philippines, and Northern Australia.
Current and Historic
Starting in the nineteen seventies, the international market made an additional distinction between white and black South Sea cultured pearls. White South Sea cultured from Pinctada maxima are produced exclusively in a geographical area situated between the Indian and the Pacific Ocean. The description “white” actually includes yellow, greenish and even golden hues. Black South Sea cultured pearls come from Pinctada margaritifera cumingii, and are produced in the tropical part of the Pacific Ocean, although there are a few exceptions. The description “black” includes other dark hues.
It states that the price of one South Sea cultured pearl corresponds approximately with the price for an entire Akoya necklace of quality.
The size of South Sea cultured pearls is in the range of 7mm to 20mm, while the average size is 12mm to 14mm. size is the most striking characteristic. And off-round shapes are always measured with the smallest diameter.
There are three color groups should be distinguished. The largest price difference is between colors of the first group which are considered very good, and colors of the second group, which are considered good. All other colors, which are less rare, belong to the third group with lower prices.
Pearls with a pink or golden body color belong in the first group; these are pearls with a white, silvery white or silver body color and a pink overtone. The second group is made up of pearls with a white, silvery white or silver body color and overtones other than pink. The thirds group includes cream, yellow and green hues.
Overtone
The iridescence of South Sea cultured pearls mainly manifest in an overtone which consists of one or several transparent colors. Pink, green, grey and blue are seen most often, but overtones are more subdued in comparison to Akoya cultured pearls.
The luster of South Sea cultured pearl is not usually as bright as the luster of Akoya cultured pearls and it I rarely classified as “very good”. The light source is usually less clearly reflected and details of the reflected image are not as sharp. This is because of the coarseness of the aragonite platelets, which have a thickness of 0.5 to 1.5 microns. The luster of a South Sea cultured pearl can be classified as “good” if light is reflected from the centre of the surface of a pearl.
The pearl Mollusks
The gold and silver lip Pinctada maxima are found in Japan, and Pinctada margaritifera which is used to culture black pearls comes from Burma in Japan, too. Australia cultured pearl industry uses the large silver lip Pinctada maxima.
Pinctada maxima can reach a length of more than 30cm and represents the largest species. The average weight is 2 kilograms, while maximal weight can reach 4.5 KG.
Until recently, it would not have been necessary to pay special attention to South Sea cultured pearls’ nacre thickness, as it was general classified as “very good”, and ranges from 1.5mm to 5mm, and the average nacre thickness is 2mm to 4mm.
In Australia, underwater cameras constantly monitor the mollusk, and specially equipped aluminum cleaning boats move between the longline systems all the time. High-pressure cleaning machinery has now replaced the hand cleaning. The high cost investment is used to maintain the well-cleaned mollusk and for leading to faster yield of high-quality pearls and are more suitable for second or third operations.
The South Sea cultured pearls’ colors are not bleached or dyed and nearly most of them are natural.
They are famous because of their large size. With South Sea cultured pearl’s relative scarcity, large size, extended cultivation period, thicker nacreous coating, natural color and difficult culturing process, South Sea cultured pearls command high prices throughout the world.
