A Closer Look: Akoya Pearls

It is important to realize that almost all pearls available on the market today are in fact cultured, and that finding saltwater pearls in their natural state is almost unheard of.

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The difference between natural and cultured pearls focuses on whether the pearl was created spontaneously by nature – without human intervention – or with human aid.

Akoya Pearls are saltwater pearls, and the name “Akoya” comes from the oyster that produces the pearl. Akoya pearls are cultured in the Pinctada fucata martensii, also known as the “akoya oyster”.

Kokichi Mikimoto is often credited with the invention of the cultured pearl process, but it was actually British Biologist William Saville-Kent in Australia who was the one that did.

Kokichi Mikimoto is often credited with the invention of the cultured pearl process, but it was actually British Biologist William Saville-Kent in Australia who was the one that did.

Despite the common misperception, Mikimoto did not discover the process of culturing pearls. The accepted process of pearl culture was developed by the British Biologist William Saville-Kent in Australia and brought to Japan by Tokichi Nishikawa and Tatsuhei Mise.

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Nishikawa was granted the patent in 1916, and married the daughter of Mikimoto. Mikimoto was able to use Nishikawa’s technology. After the patent was granted in 1916, the technology was immediately commercially applied to akoya pearl oysters in Japan in 1916.

With luck 20% of the harvested pearls will be marketable and only 1 in 10 to one in 50 oysters produce a round pearl of jewelry quality. Japan exports over $200 million pearls a year.

With luck 20% of the harvested pearls will be marketable and only 1 in 10 to one in 50 oysters produce a round pearl of jewelry quality. Japan exports over $200 million in pearls a year.

Akoya oysters, from the waters of Japan, live in shoals and in water ranging in depths of 1 to 5 meters. These calm seas have few large waves and mild temperatures of 15 to 23 degrees Celsius. These perfect oceanic climates attribute to the production of some spectacular pearls with brilliant lustre and rich colours.

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Their white color and rosé overtone complement a fair complexion and are the qualities the Akoya pearl has become renowned for. Akoya colours range from white, cream and pink to silver pink.

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Although Akoyas are normally white pearls with varying overtones, some sellers offer “black” Akoyas. These pearls have in fact been treated to create darker shades “after harvest”, and are not naturally colored this way.

The Akoya oyster is the smallest pearl-producing oyster in the world. Akoya pearls are often available in the market in sizes of 3 – 10mm. A key factor in a pearl’s value is its size, with the larger pearls generally being the more prized.

akoya pearl sizes compared

Photo by: Ashley McNamara and appears courtesy of PurePearls.com

Their amazing ability and consistency in producing near-perfect round cultured pearls make Akoya pearls ideal for adorning some of the world’s finest pearl jewellery. (the most popular size for Akoyas is 6-8mm)

GRADING:

As with any other item that can appear in a wide variety of shapes, sizes, colors, and conditions, a standardized system of grading must be used when purchasing or selling pearls.

Only in this way can the pearl be described according to mutually agreed-upon and understood terms, so that both buyer and seller can determine a fair price.

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The “AAA-A system” is the major grading system used by nearly every major pearl buyer/seller in North America, and grades pearls based on their surface blemishes, luster, nacre, and shape.

The AAA – A System:

Hanadama: This is a special designation for pearls that have passed the Pearl Science Laboratory of Japan’s rigorous tests and must be accompanied by the original certificate.

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Hanadama pearls are tested for a nacre thickness of at least 0.4mm on each side for a total of 0.8mm total nacre thickness. Hanadama pearls must also be nearly flawless with no visible blemishes and an extremely high luster.

AAA: The highest-quality pearl, virtually flawless. The surface will have a very high luster, and at least 95% of the surface will be free from any type of defect. The pearl will be perfectly round, and have a mirror-like luster, and a nacre thickness (Akoya pearls only) of 0.4mm or higher.

AA: The surface will have a very high luster, and at least 75% of the surface will be free from any type of defect. The luster will be very high, and have a thick nacre. AA is still a very nice quality, but not quite as nice as AAA or higher.

AA grade Akoya pearls are found in most average jewellery and Major Department Stores while AAA pearls are more commonly seen in higher-end jewellery stores.

AA grade Akoya pearls are found in most average jewellery and Major Department Stores while AAA pearls are more commonly seen in higher-end jewellery stores. Photo by: Ashley McNamara and appears courtesy of PurePearls.com

A: This is the lowest jewelry-grade pearl, with a lower luster and/or more than 25% of the surface showing defects. In many cases, if the pearl is being mounted into a piece of jewelry, it can be mounted so that the defects are hidden.

This quality has a chalky appearance and thin nacre, typically of .25mm or less. This thin nacre is usually due to early harvesting of the pearl.

Even this system, however, can become misleading if a seller uses terms from the grading system (such as “AAA”), but uses them to describe a different quality pearl than that which the system is generally understood to be describing.

For reasons such as these, it’s extremely important when purchasing pearls to be absolutely certain of the meaning of any descriptive terms used by the seller.

If possible, ask to see a written description of each grading term, so that you know exactly what the grade implies. Reputable jewelers will be more than happy to comply with such a request.

Length:

When it comes to describing the length of pearl necklaces a special vocabulary is used:

Strand Lengths for Posts

  • A “collar”, measuring 10 to 13 inches or 25 to 33 cm in length, sits directly against the throat and does not hang down the neck at all; collars are often made up of multiple strands of pearls.
  • “chokers”, measuring 14 to 16 inches or 35 to 41 cm in length, nestle just at the base of the neck.
  • A strand called a “princess” length, measuring 17 to 19 inches or 43 to 48 cm in length, comes down to or just below the collarbone.
  • A “matinee” length, measuring 20 to 24 inches or 50 to 60 cm in length, falls just above the breasts.
  • An “opera” length, measuring 28 to 35 inches or 70 to 90 cm in length, will be long enough to reach the breastbone or sternum of the wearer.
  • A pearl “rope”, measuring more than 45 inches or 115 cm in length, is any length that falls down farther than an opera.

Pearls can be identified by their pearly lustre and when rubbed gently against the teeth, a slightly rough surface texture can be detected, whereas imitation pearls feel smooth.

However, the only definitive way of distinguishing between natural and cultured pearls is to examine their internal structure. Experts use endoscopes to do this through the drill holes of pearls and sometimes even x-ray technology is required.

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Pearls are very susceptible to damage from chemicals and the environment so special care needs to be taken when wearing them, as well as storing them.

You will find our article “How to Clean Your Pearls” very usefull for providing your pearls with the proper care they deserve.

After all, they are the only gemstone that is made by a living creature!

We hope this article has given you a bit more of a background on Akoya saltwater pearls, but should you have any additional questions about this or any other jewellery related topics, you can always: “Ask Our Jeweller”

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This article was compiled from my personal knowledge as a gemologist, as well as numerous online sources, individuals and textbooks. If you have something to add to this article that you feel would be of benefit to others, please, do not hesitate to contact us.

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