Saltwater Cultured Pearl
Freshwater Cultured Pearl
South Sea Pearl
In general, pearls are classified as saltwater cultured pearls or freshwater cultured pearls, and are divided into the white category or the fancy color category. They are further separated by their shape as round or baroque.
Each variety of pearl available today depends on the type of oyster that produced them, the physical environment in which they live, and varying cultivation techniques used by the producers. These factors affect a pearl’s luster, shape, radiant color, and overall value.
There is a pearl for every age, every occasion, every personal style, and every budget. With endless possibilities, knowing where to begin can be overwhelming. The key to finding your perfect pearl is knowing what types are available, how they compare to each other, and how to recognize quality differences.
Not to be confused with a cultured pearl, natural pearls grow in “wild” mollusks, namely oysters and mussels, spontaneously forming in nature without any human intervention. The process of a natural pearl begins when an irritant such as a shell fragment, a scale, or parasite becomes lodged inside the oyster or mussel. To protect itself, the mollusk coats the irritant with thousands of layers of nacre, the same substance that lines the inside of shells commonly referred to as Mother of Pearl. The pearl continues to be coated with nacre and grow in size as long as it remains in the mollusk. A cultured pearl is formed in much the same way, but unlike the natural pearl, the process is stimulated by human intervention with the insertion of an irritant.
Although natural and cultured pearls are extremely similar, the key difference lies in the thickness of the nacre. Because the tiny particle at the center of a natural pearl is typically smaller than the implanted nucleus of a cultured pearl, the nacre of a natural pearl is relatively thicker. With cultured pearls, the size, shape, and position of the implanted nucleus heavily determines the final qualities of the pearl whereas with natural pearls, its qualities are determined more specifically by the type of irritant and water conditions.
Today, natural pearls are very rare and almost non-existent in the retail market. In addition to the fact that most natural pearl oyster beds were depleted by over-harvesting in the 18th and early 19th centuries, only 1 in 10,000 oysters will actually produce a pearl naturally in the wild, and of those, only a small percentage achieve the size, shape, and color to be considered gem quality. Fortunately, for all pearl lovers, by 1905 a Japanese native by the name of Kokichi Mikimoto introduced the first technique of growing perfectly round pearls artificially by implanting a nucleus inside an oyster. As Mikimoto expanded and perfected his pearl production techniques, cultured pearls gained worldwide acceptance, and by the 1930s natural pearls became a thing of the past only to be found in museums and antique estate sales.
Saltwater Cultured Pearl
Cultured saltwater, or “sea” pearls come from oysters in oceans, seas, gulfs, and bays and are produced in different parts of the world including Australia, French Polynesia, China, Japan, Thailand, Vietnam, Korea, Malaysia, Indonesia, the Philippines, Mexico, and The Cook Islands. The best known among the “white” pearls are the Japanese Akoya and the larger South Sea pearls. Naturally black cultured pearls from Tahiti and The Cook Islands are most popular among the “fancy color” pearls.
Culturing a pearl within an oyster requires a significant amount of expertise, time, and dedication. After selecting the perfect oyster for pearl production - oysters with thick shells and beautiful interiors are optimal candidates, a nucleus is delicately inserted into the oyster. Every pearl nucleus is created from freshwater mussels, called pig-toe-shell, found in the Mississippi River. After insertion of the pig-toe-shell nucleus, the oysters are returned to the sea where they are submerged in wire-mesh baskets and hung from specially designed floating rafts to protect them from natural enemies. Constantly and carefully monitored for extreme temperature changes, red tides and other oyster predators, the oysters are left submerged. During this time, the nacre forms around each nucleus. Amazingly, by the end of this process, each oyster will have covered the nucleus with thousands upon thousands of layers of nacre to form a beautiful lustrous pearl. Depending on the size and quality desired, the pearls are harvested after 2 to 3 years of cultivation.
Aside from one significant difference, the basic process of pearl producing is the same in both saltwater and freshwater pearls. To manufacture a pearl, the freshwater mussel requires the insertion of a piece of mantle tissue alone, whereas with the saltwater oyster, a round bead nucleus is inserted in addition to the piece of mantle tissue. This nucleus is often times rejected or causes the oyster to die. Just 30 to 35 percent of these oysters actually produce a pearl of which only a small fraction will be of fine quality.
Saltwater cultured pearls command higher prices than freshwater cultured pearls for several reasons. The costs and risks of producing saltwater pearls are much greater due to the higher costs incurred in obtaining the shell bead nucleus, extra labor for the skilled technicians to perform the implant surgery, and because a significant number of oysters are required for a good yield. However, the most important reason for the cost difference is related to the simple economics of supply and demand. Compared to freshwater mussels that can produce 40 to 50 pearls at a time, the saltwater oyster is limited in its production to just 1 to 2 sizeable pearls.
With respect to quality, saltwater pearls acquire properties from the sea that not only provide for a deeper luster and orient but also preserve their beauty for generations. Furthermore, historically oceanic pearls have been highly valued for their rarity. Early pearl fishers risked their lives facing the many dangers of the deep sea while diving for the precious gems.
Freshwater Cultured Pearl
Freshwater cultured pearls are grown in freshwater rather than saltwater, and not in oysters but in mussels living in lakes and rivers. Freshwater pearls are produced by the Hyropsis Cumingi mussel, which is roughly the size of a human hand. The leading countries in the production of freshwater pearls are the United States, China, and Japan. China has become the leader in this pearl type by developing new freshwater culturing techniques. Nearly 96% of freshwater pearls today are produced in China with much higher quality, even making them comparable and indistinguishable from their saltwater cousins. The Japanese also have a rich history of freshwater pearl cultivation. Pearls from Lake Biwa are recognized worldwide as the quality standard. Sadly, in the 1970s freshwater pearl production stopped completely as Lake Biwa became toxically polluted. While the Japanese are just at the beginning stages of restarting their freshwater pearl production, they are achieving successful results.
Differing from that of saltwater pearls, the process of cultivating freshwater pearls does not require a bead nucleus. By using grafting techniques, a mantle tissue is introduced to the mussel. This method along with the fact that a larger mollusk is used for freshwater production, allows for mass production. A single mollusk can produce up to 50 pearls at a time.
Freshwater pearls are available in a wide range of colors, shapes, and lusters. Colors include orange, lavender, purple, violet, blue, rose, and gray just to name a few. Another allure of the freshwater pearl is the variety of shapes available. In addition to the round cultured pearl, which requires more sophisticated production techniques, freshwater pearl producers are also culturing pearls in special fancy shapes such as crosses, bars, and coins. Typical sizes of freshwater pearls range from 4 to 10mm.
In addition to the versatility offered by the many color and shape options, the lower cost of freshwater pearls makes it an attractive value alternative to the saltwater pearl.
Akoya Pearls are produced by the saltwater Akoya Oyster (Pinctada Fucata Martensii), the smallest pearl producer in the oyster family. Depending on the size of the oyster, pearl size varies between 2-10mm. The range of colors of these pearls include white, cream, pink, blue, green, silver, and gold.
Originally cultivated in Japan, the finest Akoyas are more perfectly round than most other pearls and are known for their high luster and rich color. Unfortunately, for those who have a preference for larger pearls, they rarely exceed 10mm and when they do are exceptionally expensive. In addition to Japan, China is now a major producer of Akoyas.
The fascinating story of the cultured Akoya Pearl begins back in the late 1800s when Kokichi Mikimoto began to experiment with pearl cultivation. In 1893 Mikimoto introduced the first pearl ever cultured by man and by 1905, after 12 years of tireless research, he mastered the art by successfully culturing a pearl with a perfectly round shape.
To produce an Akoya Pearl, a nucleus bead is surgically implanted in the body of the oyster. This bead is then coated with layers upon layers of nacre. The ideal water temperature is preferably near 20 Celsius (68 F), which allows the slower formation of quality nacre. This condition along with the compacting of aragonite crystals found in the water during seasonal changes provides for the exceptionally beautiful Akoya Pearl luster.
Inspired by the work of Mikimoto, the pearl industry today is intimately associated with Japan. The largest habitat in the world for Akoya oysters covers half of the sea around southern Japan. In the last 100 years, Japanese pearl farmers have continued to refine their techniques and have made pearl production an art. Their attention to detail has resulted in the most beautiful Akoya Pearls in the world.
Better known throughout the world as Black Pearls, cultured Tahitian Pearls are indigenous to the lagoons of French Polynesia in the South Seas. The only pearls in the world that are naturally black, Tahitian Pearls are grown in the large black lipped oyster Pinctada Margaritifera. These saltwater oysters can grow as large as 12 inches in diameter and produce pearls typically ranging in sizes from 8 to 18mm. With the skillful efforts of Japanese cultivation experts, the first Tahitian pearls were cultured in the 1960s.
Contrary to popular belief, Tahitian pearls are not cultivated in Tahiti, but rather throughout the waters of French Polynesia as far east as the Gambier Islands and west into the Micronesian Islands. As French Polynesia’s most well known island, Tahiti remains the commercial center and trading hub for these rare and exotic Black Tahitian Pearls.
Tahitian Pearls are not simply “black” as they are commonly called, but are rather more accurately represented by a rainbow of colors including shades of gray, silver, charcoal, and green just to name a few. Many stories and legends exist in Tahiti to explain how the pearls’ iridescent and entrancing colors came to be. The four basic shapes of Tahitian pearls include round, semi-baroque, baroque, and circled. As with other pearl types, rounder pearls exhibiting a high luster with fewer flaws command premium prices. In addition, special color combinations such as “peacock” and “pistachio” carry a higher value because of their rarity.
South Sea Pearl
Cultivated in the waters off Australia, Indonesia, the Philippines, Myanmar, Japan and Thailand, the South Sea Pearl is the most rare and valuable among cultured pearls. The South Sea Pearl typically ranges in size between 10 to 20mm with the average pearl measuring 11 to 14mm. Produced in the rather large oyster Pinctada Maxima, the culturing process of the South Sea Pearl is more extensive as compared to other cultured pearls. The oysters used are a wild species and supply for cultivation is never certain. In addition, the South Sea Pearl oysters are nurtured in isolated bays of the purest waters, far away from industrial areas.
Depending on the variety of the Pinctada Maxima oyster, these exceptionally rare and extraordinary South Sea pearls come in different lustrous colors. The silver lipped oyster produces pearls in the white, silver, aqua, and blue family of overtones, while the gold lipped oyster pearls exude cream, champagne, vanilla, and deeper golden tones. The natural colors of South Sea Pearls are truly rich and beautiful and need no enhancement to bring out their soft satin-like glow.
The legacy of the South Sea Pearl goes back thousands of years when early Australians used oyster shells, along with the pearls found in them, not only as decorations for their tribal costumes but also as currency to trade for food and tools. With the arrival of the European explorers in the 16th and 17th centuries, the South Sea Pearl became a precious global commodity. In high demand by the 18th century, over-harvesting lead to near extinction of the South Sea Pearl producing oyster. By the 1930s strict regulations were imposed to protect the industry and it wasn’t until the 1950s that South Sea Pearl farms began producing harvests of commercial value.
These rare natural pearls are harvested from the Queen Conch technically known as Strombus Gigas, from the waters along the coasts of Florida, Bahamas, Yucutan, and the Antilles Islands. Unlike other pearls, the Conch pearl cannot be cultured by using the traditional pearl techniques due to the nature of the Conch itself. The sensitivity and complicated spiral structure of the snail shell makes it impossible to reach the pearl forming area without damaging it. Every year no more than 3000 conch pearls are harvested and only 15 to 20% are suitable for making jewelry. Another factor that adds to the rarity of these valuable pearls is the increasing problem of worldwide environmental pollution that has lead to the drastic reduction in the number of Queen Conch. A ten-year fishing ban was recently enforced off the coasts of Colombia as an effort to protect these rare snails from extinction. .
These distinctively unique and strikingly beautiful pearls are characterized by a wavy flame structure that gives the appearance of a fire burning on the surface. The Queen Conch produces pearls in a wide variety of enchanting colors: white, pink, cream, olive, brown, beige, yellow, orange, and red. The most valued of these pearl colors are red and pink, which oftentimes show a wavy structure resembling the finest silk.
Like other gemstones but different from cultured pearls, the conch pearl is measured in carats with the average pearl weighing between 2 to 6 carats.
A pearl the size of 8 to 12 carats is rare and of extremely high value.
Half spherical cultured pearls grown on the inner shell of the oyster referred to as Pteria Penguin, Mabe Pearls are primarily found in the tropical seas of Southeast Asia and in the Japanese islands around Okinawa. Mabe Pearls have a beautiful, rainbow colored iridescence that ranges from light pink, dark rose to slight bluish shades gleaming with a metallic luster. Having a flattened side, Mabe Pearls are an ideal choice for jewelry such as earrings and rings that allow for a secure setting and a concealed flat back.
The process of culturing Mabe Pearls, or half pearls as they are often referred to, begins with the gluing of a plastic nucleus to the inside of the shell. Once the hemispherical nucleus is covered with nacre, the pearl is carefully cut away from the inner shell, its bead is taken out, and the cavity filled in with a resinous paste and backed by a mother of pearl plate. Depending on the shape of the nucleus, unique shapes of half pearls can be achieved such as ovals, drops, and hearts.
Often referred to as seed pearls, Keshi Pearls are produced as a bi-product of
the culturing process. When an oyster rejects its bead implant and particles of
the mantle tissue used alongside the bead remains, this stimulates the production of nacre and an essentially all nacre Keshi Pearl is born.
Keshi Pearls are quite small in size, come in a wide variety of shapes, and occur in virtually all shades of color.
Today these lustrous all nacre pearls are becoming exceptionally hard to find as South Sea Pearl farmers are improving their abilities and increasing their efforts to reduce the production of these Keshi Pearls. Since each oyster can only produce a limited amount of nacre, allowing a Keshi Pearl to grow leaves less for the cultured pearl being produced simultaneously within the same oyster. As the farmers x-ray each oyster to see whether or not the nucleus is still inside, they have the opportunity to re-nucleate and not allow the Keshi Pearl to develop.
Requiring anywhere between 8 to 10 years to form, the Abalone Pearl is one of the most beautiful and rare of all pearls. Mostly natural pearls, they are found off the Pacific Coast of the United States, Japan, New Zealand, and Korea. Attempts at culturing these pearls have been met with much difficulty and production has been limited to only Mabe Pearls, also called “half pearls”.
Much like their Mother of Pearl shells, Abalone Pearls are treasured for their exquisite color and highly iridescent nacre. These pearls vary greatly in color including blue, green, magenta, pink, gold, bronze, gray, silver, cream, purple, and beautiful combinations of these multiple colors. The most rare and valued colors are rich magenta, peacock blue, and green.
Another distinguishing characteristic of Abalone Pearls is their shape. Usually baroque in shape, many are horn or tooth-shaped. A perfectly shaped Abalone Pearl is virtually nonexistent but when found will be exceptionally expensive.
Melo Pearls are produced by a very large marine snail called the Indian Volute, otherwise known as Melo Melo. These rare pearls are primarily harvested in Vietnam but also found in other Southeast Asian waters. Extremely large and generally very round in shape, their luster resembles that seen in conch pearls. Typical colors include yellow, orange, reddish, tan, and brown. All Melo pearls are natural pearls given that to date no one has been able to cultivate them.
Valued for centuries by Native Americans living along the Atlantic Coast of New England, the Quahog Pearl is absolutely beautiful and one of the most precious in the world today. These pearls are produced by the clam Venus Mercenaria. Most Quahog Pearls exhibit a soft satiny luster like fine porcelain. The Quahog pearl occurs in a range of colors including white, pale lilac, purple, brown, and black; with the most desirable color being in the lilac to purple range. Shapes vary from round, oval, and teardrop, to button. These pearls are usually small but can reach 18-20mm.