Pearl Knowledge

Akoya pearls

 Akoya pearl is saltwater pearl cultivated from the akoya oyster. It is commonly known as cultured pearl. Their almost perfectly round shape and extraordinary luster make them the most popular type of pearl jewelry. Akoya pearl demands more market value than freshwater pearl of comparable quality because of their popularity and rarity.

The creation of akoya pearls is like any other saltwater pearls. The akoya oysters are nucleated with a bead of mother of pearl. The size of akoya pearls are mostly smaller than that of other type of pearls, ranging from 4 to 9 millimeters. Most akoya pearls are white, cream or golden in color with rose or peacock green overtone color. There is no natural black color akoya pearl. The black akoya pearl existing in the market is not a natural color pearl.

Traditionally, Japan is the primary source of cultured akoya pearl. In recent years, Japanese akoya pearl production declined dramatically because of water pollution, disease and market competition. Chinese akoya pearl has become the major source in the pearl market worldwide. The Japanese now import most of their smaller akoya pearls from China and then process and sell them as Japanese akoya pearls. The vast majority of akoya pearls under 7.5 mm in the market are produced in China. However, Japanese still dominates the market of higher quality larger sized akoya pearls.

 Freshwater Pearls

Freshwater pearls are the pearls created from freshwater mussels or mollusk. They were historically produced in Japan, but are now exclusive to China.

Cultured freshwater pearls are created by manually implanting a tiny piece of mantle tissue inside the mollusk. The mantle tissue becomes the nucleus around which the mollusk secretes layers of nacre (the substance that forms the pearl). The freshwater mussels can be implanted as many as 24 to 36 mantle tissues to form potential 24 to 36 pearls. Freshwater pearl can be cultured in lakes, ponds or rivers. The size of freshwater pearls can range from 4mm to 14mm. Their shapes are rarely perfectly round and less lustrous comparing with the same quality akoya pearls. But they have very thick nacre (almost 100% nacre. Freshwater pearls are the most common pearl for jewelry because of large supply, attractive price and variety of shapes and colors. Natural colors of freshwater pearl include white, cream, pink and lavender. Shapes can be baroque, potato, rice, half round, button and round.

 Cultured pearls

The formation process of cultured pearl is same as that of natural pearl, except in cultured pearl, the human implants the nucleus around which pearl was formed. But in natural pearl, the nucleus is the microscopic intruder or parasite entered by accident.

Basically two types of cultured pearl exist - saltwater cultured pearl and freshwater cultured pearl. South Sea pearl, Tahitian pearl and akoya pearl are saltwater pearls. Almost all freshwater pearls originated from China. More than 80% of akoya pearls also produced in China with the rest from Japan. South Sea pearls are from Australia, Philippines, Burma and Indonesia. Tahitian pearls come from Polynesian islands in South Indian Ocean. Because of rarity, beauty, luster, size, difficulty of farming, limitation of environment, natural disaster, saltwater pearl are more valuable than freshwater pearl under comparable quality. Among saltwater pearls, South Sea pearl commands highest value, Tahitian pearl comes the second. Akoya pearl are the third. Because of its affordability, excellent luster and consistently round shape, akoya pearls are the most popular pearl jewelry.

Almost all pearl jewelry in the market is made of cultured freshwater/saltwater pearl instead of natural pearl.

Today, "cultured pearl" is still used to describe akoya pearl. Because seller of freshwater pearl may describe it as cultured pearl, which is not wrong? It is important to know whether it is freshwater pearl or akoya pearl when the seller describes it as "cultured pearl" because akoya pearl is much more valuable than freshwater pearl under comparable quality.

Tahitian pearls

Tahitian pearls come from French Polynesian islands and Micronesian Islands. They are cultured from large Black-Lipped Oyster, or Pinctada margaritifera which is the only oyster to produce natural black pearls. Unlike other types of pearls, Tahitian pearls have naturally black body color with full spectrum of overtone colors. Tahitian pearls are bead-nucleated with very thick nacre (minimum 0.8 mm).

The most common size of Tahitian pearls is in the range of 9 mm to 13 mm with round to baroque shape. Some can be up to 20 mm in size. Tahitian pearl is the only type of pearls that has full spectrum of colors. Vast colors make matching these pearls a difficult task. Tahitian pearls were once the most valuable cultured pearls in the world. Today, it is more affordable but still expensive. Tahitian pearl is only second to South Sea pearl in both size and value.

South Sea pearls

South Sea pearls come from Australia, Philippines, Indonesia, Burma and some other South East Asian countries. White South Sea pearls are cultured in Northwestern Australia. Golden South Sea pearls are produced in some South East Asian countries. White-lipped oysters generally produce white pearls with silver, aqua and blue overtones. The gold-lipped oysters produce golden, cream and champagne colored pearls.

The size of South Sea pearls can be from 8mm to 20mm, commonly in the range of 11mm to 13mm. Very few South Sea pearls are round or near round. Round and matched South Sea pearl strands are even rare. Majority of the harvest is off round, drop-shape and baroque. These irregular shape pearls are often used in high-end designer jewelry. Unlike Akoya and freshwater pearls, South Sea pearls generally are not necessary to be processed after harvesting.

The rarity, the beauty, the unusually large size and extended growth period (3-6 years) make South Sea pearls the most valuable pearls. It is not uncommon for the retail prices of high-quality South Sea pearl necklaces to be in the range of $100,000 to $200,000 in high end retail jewelry store.

Saltwater pearls

Pearls produced in oysters inhabiting saltwater are saltwater pearls. The three most common types of saltwater pearls are South Sea pearls, Tahitian pearls and Akoya pearls.

Saltwater pearls tend to be rounder than freshwater pearls. This is because saltwater oysters are bead nucleated.

Saltwater pearls are more valuable than freshwater pearls with South Sea pearl highest, Tahitian pearls second and Akoya pearls third with equivalent quality.     

Baroque pearls

Baroque pearls are the pearls with irregular shape.

Freshwater pearls are more often to be baroque because they are not bead nucleated as saltwater pearls. The mantle-tissue nucleated freshwater pearls tend to be developed in different irregular shape.

Baroque akoya pearl differs from that of a freshwater pearl.  Semi-baroque Akoya pearl has a water-drop shape or pear shape. Baroque akoya pearl has small tail behind a rounded front.

The amount of time cultured will increase the thickness of nacre and the luster. At the same time, it will also increase the chance of producing a baroque pearl.

Mabe pearls

Mabe pearls are grown against the inside shell of an oyster. They have hemispherical shape. The colors of mabe pearl range from light pink, white, to bluish. They are generally used as earrings or rings. Mabe pearls mostly are produced by saltwater oysters. Most mabe pearls are produced in Japan, Indonesia, Polynesia, and Australia. Mabe pearls are not as valuable as full round pearls.

Hanadama pearls

Hanadama pearl is the best possible quality of Akoya pearl. Hanadama pearls are generally considered as close to perfect in each of quality attributes such as luster, nacre thickness, color, overtones, roundness, surface. Only approximately 1% of marketable Akoya pearl qualifies for Hanadama pearl. All Hanadama pearls are evaluated and certified by the Pearl Science Laboratory in Tokyo and should be accompanied with an identifying certificate. Because of scarcity of Hanadama pearls, they command a substantial premium in price.

Natural pearls

Natural pearls are formed when a microscopic intruder or parasite enters a bivalve oyster by accident, and gets embedded inside the shell. The oyster, being irritated by the intruding foreign object, secretes the nacre to cover the irritant layer by layer. As a result, Natural pearls are formed. Natural pearls come in irregular shapes. Round natural pearls are very rare.

Creation of pearls

A pearl is formed when a foreign object gets into the shell of oyster or mollusk and becomes embedded in the tissue. In response, oyster or mollusk builds up layers of nacre surrounding the irritant and gradually forms a pearl.

Natural pearls are formed in nature by chance - a parasite or a piece of organic object accidentally embedded in the gonad or mantle tissue of an oyster or mollusk. Cultured pearls are formed by human intervention - inserting a foreign object into the tissue of an oyster or mollusk. But the process of pearl creation is same for both natural pearls and cultured pearls. The only difference is that natural pearls are created accidentally; but cultured pearl is created intentionally.

Freshwater pearl vs akoya pearl

 The main differences between cultured freshwater pearls and akoya pearls are the culturing process, the nucleus, the shape and the value.

Freshwater pearls are mantle-tissue nucleated by inserting a tiny piece of mantle tissue directly into mantle tissue of a freshwater mussel, whereas akoya pearls are bead-nucleated by inserting a mother-of-pearl bead and a piece of mantle tissue into the gonad of akoya oyster. Therefore, freshwater pearl is composed of almost solid nacre. Akoya pearls may only have .1 to 2 mm nacre over a bead nucleus.

Freshwater mussel can be inserted 12 to 16 times per valve, producing up to 32 pearls. An akoya oyster can generally be inserted 1 to 2 times with a shell bead and tissue piece into its gonad.

Freshwater pearls are much easier to farm than akoya pearls. Their successful harvesting rate is much higher than that of akoya pearls. The implanting operation and training are also much easier with a freshwater mussel.

Akoya pearls have higher quality attributes than freshwater pearls. Freshwater pearls are rarely round in shape, whereas akoya pearls are generally round. Freshwater pearls do not have the good luster of akoya pearls. Although harvested freshwater pearls have solid nacre, and akoya pearls may only have only .1 to 2mm of nacre over a bead-nucleus, akoya pearls are generally considered more valuable because of their excellent luster, consistently round shape, rarity and popularity.

Freshwater pearl vs cultured pearl

Cultured pearls are created in nature with human intervention. Cultured pearl exists in two categories - freshwater cultured pearl and saltwater cultured pearl (akoya, Tahitian and South Sea). But "Cultured pearls" is still commonly used today to refer to akoya pearl. It is important to know that a seller can describe freshwater pearl as cultured pearl which is not wrong. Just make sure whether it is freshwater pearl or akoya pearl when they describe as "cultured pearl" because freshwater pearl is less valuable than akoya pearls with equivalent quality.

How are cultured pearls grown?

 Implant the Nucleus

Technicians open the live pearl oysters or mollusk gently, then surgically implant a small shell bead (mother of pearl) along with a tiny piece of mantle tissue (commonly for saltwater pearls) or only a tiny piece of mantle tissue (commonly for freshwater pearls). This bead or mantle tissue is the nucleus around which the oyster or mollusk secretes layers of nacre (the substance that forms the pearl). Culturing process requires skill and precision - especially for akoya pearl culturing process. It takes months even years to master the process. Technicians need exact tools to make precise operation.

Back to Water

The nucleated oysters or mollusks are quickly returned to the natural water such as sea (saltwater pearls) or lake/river (freshwater pearls), housed in suspended individual mesh pockets. The oysters or mollusks feed and grow in water bodies rich in natural nutrients. As time goes by, the oysters or mollusks secrete layers of nacre around the implanted nucleus.

Caring Oysters

Oysters have to be lifted from the sea for cleaning and health care and treated with compounds to prevent parasites from injuring the oysters periodically. These oysters have to be protected from every threat such as typhoons, red tides and predators to ensure best harvest of pearls.

Harvesting Pearls

The pearl farmers bring the oysters or mollusks back to shore to harvest. Comparing with freshwater pearls, akoya pearls have much lower successful rate. Only a tiny fraction of them produce high grade pearls. Less than five percent of the harvested pearls are considered fine quality. The few marketable pearls are then cleaned, soaked, and sorted.

 How to choose pearl necklace?

Choosing necklace length

Pearl Collar: 12" - 13", usually made by multi-strands and worn high on the neck, ideal to boat neck, V-neck, or off-the-shoulder fashions. Very popular during the Victorian era, making a comeback now.

Pearl Choker: 14" - 16", worn lower on the neck, appropriate from casual to formal eveningwear, classic and versatile length.

Princess Necklace: 17"-19", the most common length of pearl necklace, lying slightly below the neck, a versatile style, well suited for both high and low necklines.

Matinee Necklace: 20"-24", works well with suits and dresses, looks best with high necklines and adds sophistication to a professional look.

Opera Necklace: 26"-36", traditionally worn with eveningwear, can be worn as a single strand or double strand, can also be knotted to create a stylish look.

Pearl Rope: over 37", can be worn as single, double or triple strand, can also be knotted for a fashionable look, very popular trend today.



Choosing pearl size

Traditionally, certain pearl sizes are considered appropriate for women of various ages. The size of the pearls is also considered as an indicator of wealth and social status. But the versatility of a pearl strand should not be limited by such rules, and should be a matter of personal taste.

Smaller pearls (less than 6 mm) are generally considered to be appropriate for teenage girls or younger women. This pearl size is often given as a sweet sixteen or high school graduation gift.

Pearls with size of 6 mm - 8 mm are traditionally worn by women in their 20s or 30s. A necklace of these pearls makes a perfect gift for a birthday, college graduation gift, or a bride on her wedding day.

Pearls with size of 9 mm - 10 mm are traditionally worn by women in their 40s. These pearls tend to be more expensive and associated with financial success. Ideal for sophisticated ladies with refined and elegant taste.

Pearls with size of larger than 11 mm are generally worn by wealthy women of more mature years because they are rare and more expensive. Perfect as a special anniversary gift.

Japanese vs Chinese akoya pearl

Japanese Akoya pearl had monopolized the whole pearl industry in the last century. But that has come to an end. Because of pollution, disease and competition from China, Japanese Akoya pearl production decreased dramatically in the last decade. Chinese Akoya pearl has become the major source of the pearl industry. Today, more than 80% Akoya pearl sold in the market originate from China.

Most companies in Japan are now turning to China as their main pearl source. They are the largest buyers of Chinese Akoya pearls. The pearls are imported from China to Japan, processed, and tagged "Made in Japan", then sold at much higher price than Chinese Akoya pearls.



Most Japanese Akoya pearls originate from China except larger sized (more than 8 mm) Akoya pearls. Jewelers Circular Keystone which is the undisputed industry authority since 1869 has recently announced that the phrase "Japanese Akoya Pearls" is no longer an accurate industry term, and should not be used.

Today, Chinese can culture same quality smaller sized Akoya pearls (less than 8 mm) as Japanese. But they have not yet mastered larger sized Akoya pearl (more than 8.5 mm) farming technique.

Pearl caring

Caring for Your Pearls

Pearls is a delicate organic gemstone which can be easily scratched, cracked, and damaged. In addition, some personal care products such as perfume and hair spray can reduce pearl's luster. Therefore, pearl jewelry needs special care. This will help to protect the luster and beauty of your pearls.

The following are the tips to protect your pearls:

Store pearls separately from other jewelry to avoid getting it scratched or damaged. Store them in soft cloth pouch or in a soft-lined jewelry box instead. Do not store pearls in a sealed plastic bag which may reduce luster of pearls or an excessively dry place which may cause pearls to become brittle.

Minimize contact with personal care products. Cosmetics should be applied before the pearl jewelry is put on. Take your pearl jewelry off when they might contact any possible damaging substances such as chlorine in swim pool, soap, etc.

Minimize contact with perspiration which can dull the pearl's luster. Remove your pearl jewelry before exercising or carrying heavy work.

Clean your pearls after wearing with a soft damp cloth and wash your pearls periodically with a mild soapy water (not a detergent) to remove build-ups. Do not hang pearls to dry as this may stretch the silk thread, place on soft towel or cloth to dry instead. Never use toothbrushes, scouring pads or abrasive materials to clean pearls.

Do not expose your pearl jewelry to strong light for an extended period of time which may cause pearl's color faded.

Restring your pearls periodically to prevent breakage.

Pearl colors

Pearls come in various colors such as white, cream, golden, rose, pink, gray, black, etc. The color of pearls is an important value factor of pearls.

The color of a pearl can be a combination of body color, overtones and orient.

The body color is its main color. Overtones are translucent colors over body color. The typical overtone color is white pearl with rose overtones. Orient is iridescent colors which changes when pearl is moved .

Most Tahitian pearl comes with black, peacock blue, or gray color. South Sea pearl comes in white, cream, or golden colors. Akoya pearl come in white, cream, golden and gray color. White body color often has rose overtone color. Freshwater pearl comes in white, cream, pink, rose color. There is no natural black color for akoya pearl and freshwater pearl.

Pearl grading

WinPearl.com adopted AAA+ to A quality grading system with AAA+ the highest quality and A- the lowest quality. We try to describe our product as accurately as possible. In addition to the quality grade of each product, we have more detailed product description to help our customer make purchasing decision.

Pearl history

A century ago, pearls were harvested in the wild from ocean floors and river bottoms. It was extremely difficult to find a naturally formed round pearls.

Today, almost all pearls used for jewelry are cultured pearls. Large quantity of round pearls are produced by using pearl culturing technique first developed by Tatsuhei Mise and Tokichi Nishikawa in Japan.

Nishikawa was the one granted the patent in 1916. The technology was commercially used for akoya pearl culturing in Japan in 1916. Mise's brother was the first one to produce commercial akoya pearls. Nishikawa married the daughter of Mikimoto. Mikimoto used the technology after the patent expired in 1935.

Mitsubishi first used the technology to successfully produce a cultured South Sea pearl in 1931, but the project was discontinued at the beginning of WWII before significant productions of pearls were achieved. After WWII, the South Sea pearl projects were re-started in Burma, Kuri Bay and Port Essington in Australia.

Pearl farmers began culturing freshwater pearls using the pearl mussel’s native to Lake Biwa in middle of 1910s. Because of tremendous success, "Biwa pearls" was at one time nearly synonymous with freshwater pearls.

The original Japanese akoya pearls were produced by a species of small oysters, Pinctada fucata martensii, which are no bigger than 6 to 7 cm in size. Today, a hybrid oyster (a cross between the original Japanese oyster and Pinctada chemnitzii of China) is used in both Japan and China in akoya pearls culturing.

Today, China supply over 95% of freshwater pearls and 80% of akoya pearls to the world pearl market. Japan is no longer producing smaller akoya pearls (less than 8mm). Japan is now importing Chinese akoya pearls to process and re-label them as product of Japan to export.

Pearl processing

The pearl processing is a labor intensive and time consuming process. After harvesting, the pearl has to go through a series of processing such as treatment, sorting, drilling to become pearl jewelries. Since pearl is the creation of nature, it is almost impossible to find exactly same pearls. Therefore, sorting and matching pearls needs patience.

Treatment

The harvested pearls are processed through a series of gentle treatments. They are first soaked for several days in a mild cleaning solution under intense fluorescent light to remove any deposits and odors. The pearls are then put in the natural oils such as walnut shell oil which provides a soft, gentle polish without harming the pearl.

Sorting

After receiving gentle treatments, the pearls are put into special meshes and sorted by different size groups, and then they are sorted according to shape, body color, overtone, luster, surface and finally overall quality. The matched groups are further separated into a well-matched group to make a pearl strand. Since pearl is the creation of nature, it is almost impossible to find exactly same pearls. Therefore, sorting and matching pearls are the work of art.

Drilling

Pearls are drilled through for necklaces and bracelets or half for earring studs and rings. Drilling is a very delicate operation which needs with care and precision. Pearls can be easily damaged by inexperienced operator.

Making Pearl Jewelries

After receiving the above process, Pearls are sorted into matching group. They are ready to be strung and knotted to make a necklace, bracelet or any other kinds of pearl jewelries. 

Pearl quality and value

Five factors determine the quality of pearls: nacre, luster, surface, shape and size. The thicker nacre represents the better quality. Generally, the pearl with thicker nacre has better luster and lasts longer. More lustrous pearl represents better quality. The pearl with smoother and less blemished surface has better quality. Rounder shape represents better quality. Under same size of nucleus, the bigger pearl size represents better quality because it has thicker nacre.

Three factors determine the value of pearls: type, quality and size. Under comparable quality, South Sea pearl has highest value; Tahitian pearl comes the second; Akoya pearl comes third; Freshwater pearl comes last. Obviously, for the same type of pearl, better quality is more valuable. The pearl with bigger size demands higher value under same quality.

Freshwater pearl vs saltwater pearl

Two kinds of pearls exist in the market. That is freshwater pearl and saltwater pearl. Freshwater pearls are formed in freshwater mussels that live in freshwater lakes, rivers and ponds. Most freshwater cultured pearls in the market today originated from China. Saltwater pearl grows in oysters that live in saltwater, akoya, South Sea and Tahitian pearls are saltwater pearls.