Published: October 2011
by Antoinette Matlins, PG; Gem Expert & Author of The Pearl Book: The Definitive Buying Guide and Jewelry & Gems At Auction (GemStone Press)
Not all cultured pearls are the same and they should not be grouped all together as they often are. Different types of pearls are produced by different types of mollusks. The rarest and most prized cultured pearls are produced by saltwater oysters belonging to the Pinctada genus: Pinctada maxima, which produces magnificent large pearls in an array of colors including white, cream, and fancy colors such as yellow and gold; Pinctada fucata (also known as the Akoya or the Pinctada martensii), which produces the smaller classic round white pearl; and Pinctada margaritifera, which produces the "dark" pearls, those in the gray, bronze and black hues. In addition to different species of oysters producing different types of pearls, pearls produced by the same oyster species can differ from one geographic location to another because of differences in conditions such as water temperature and nutrients. Different types of pearls and pearls from particular geographic locations have their own distinctive characteristics, their own distinctive colors, shapes, radiance and overall appeal; some are more beautiful, rare and highly prized than others, as with any other gem.
Let's take a moment to compare the pearl to ruby and sapphire. Ruby and sapphire are not considered the same thing, yet that's exactly what they are; ruby is the red variety of the mineral corundum and sapphire is the blue variety of the same mineral, corundum. They really differ only in color and rarity, factors determined by the specific set of conditions under which they formed; since nature produced the particular set of conditions required to produce ruby less frequently, ruby is much rarer. Its rich, desirable color, combined with its rarity, results in its being more highly prized and much more valuable than blue sapphire.
So it is with pearls; all true pearls are composed of "nacre," but the large, radiant white pearl created by the oyster Pinctada maxima, for example, is created by a different set of conditions--a different oyster, a different geographic environment--than smaller white pearls, or large black pearls, and so on. And just as ruby is rarer and more highly prized than sapphire, certain types of pearls, such as South Sea cultured pearls, are rarer and more highly prized than other pearl varieties.
More countries are now culturing pearls, and as a result of the differing water conditions and the mollusks used, we are now finding much greater variety in terms of size, shape, and perhaps most important of all, color. Color is now the rage, with rich golden pearls, multi-color strands, and "chocolate" pearls topping "wish lists." One of the most exciting developments in terms of color is the production of cultured pearls in Fiji. Here we are now seeing an increasing production of beautiful, intensely lustrous pearls occurring in an array of colors not seen elsewhere, in impressive sizes averaging 10.5 - 11.5 millimeters in diameter, with some reaching as large as 18 millimeters. Mexico's production of round cultured pearls has increased significantly, in a range of exotic colors (from the "rainbow-lipped” oyster, Pteria sterna, a mollusk previously believed incapable of producing cultured pearls!). While still not widely available, as production of round pearls continues to increase in number and quality; this is a pearl to watch.
Thailand and Vietnam are also finding success in round pearl culturing, and Indonesia, Malaysia, South Korea, and Thailand have increased production. The focus in the Philippines remains on creating sensual creamy to deep gold colors, and demand for natural “black”color cultured pearls from French Polynesia and the Cook Islands continues to rise. Natural black cultured pearls have also benefited from stricter controls, a reduction in the use of treatments, and the production of higher quality pearls than we've seen in the past decade, which has resulted in much stronger prices, reversing the ever-weakening prices that reflected the flooding of the market with low-quality, treated pearls in the 1990s an early 2000s.
For those who love cultured abalone mabé pearls, those from New Zealand are readily available and very popular on the fashion scene because of their affordable prices and exotic colors. Unfortunately, those from the northwest coast of California are no longer available.
China continues to bring beautiful freshwater cultured pearls to the pearl scene, in ever new shapes -- such as "petal" pearls -- in increasingly large sizes, and in a palette of colors, albeit many colors are the result of some type of treatment. China has become a major force in freshwater pearl culturing. Having begun by making small, white, near-round all-nacre pearls that were available in sizes up to 6 millimeters, today China is producing round cultured freshwater pearls reaching 15 millimeters in size. Some Chinese freshwater pearls are all-nacre—having no nucleus—but nucleated freshwater pearls are also being produced in China now. These lovely pearls, ranging in color from white to cream to lovely pastel shades of pink and lavender, are going to fill an important need in the market for large cultured pearls at a much more affordable price than the much rarer and expensive South Sea cultured pearl, which remains the “queen” of cultured pearls. Today China is also a significant producer of saltwater cultured pearls, including akoya pearls (the classic round, white Japanese pearl) and South Sea cultured pearl varieties. Chinese pearls, however, are also often treated to change or improve color and lustrousness.
This is the classic, round, white pearl cultivated in saltwater oysters primarily in Japan and China using the "akoya oyster" (also known as the Pinctada martensii or fucata). The average size is 6 - 8 millimeters in diameter, but they can reach 10+ millimeters; prices jump with each ½ millimeter size increase! Asking about nacre thickness is especially important; we are seeing an increasing number of akoyas prematurely harvested with overly thin nacre. Nacre thickness is generally described as “very thick,” “thick,” “medium,” “thin” and “very thin” and I do not advise buying cultured pearls with thin or very thin nacre.
Japanese akoyas normally have thicker nacre than Chinese akoyas. In the finest, lustrousness can be the highest of any cultured pearl, but poor quality akoyas have very low luster and look chalky. Typical colors range from white to cream to yellow; white with a pinkish overtone is the rarest. Akoya shapes are normally rounder and surfaces less spotted than South Sea varieties.
South Sea cultured pearls are produced by the Pinctada maxima oyster, many of which reach a foot in diameter. There are two varieties, readily identifiable by the unique color at the edge of the shell’s interior lining: the silver-lipped Pinctada (with its silvery white lining) produces the large, silvery white pearls associated with royalty, and the golden-lipped (with its golden lining), producing creamy to deep golden pearls. Cultivated throughout the Indian and Pacific oceans, the finest come primarily from Australia, Indonesia, and the Philippines. Burma once produced the finest “South Sea” pearls but the quality of most of the pearls now produced in Burma has declined and is often inferior to those now produced elsewhere. Naturally black pearls—often called “Tahitian” pearls—are also usually grouped with South Sea pearls although they are grown by a different variety of oyster.
South Sea pearls average 13 millimeters in diameter; pearls over 16 millimeters are considered very large, and over 18 millimeters, extremely rare. Colors include pink-white, silver-white, gray-white, cream and fancy colors such as yellow and gold and black. Oysters produce nacre at a much faster rate in the warmer waters of the South Pacific and producers adhere to a much longer cultivation period, resulting in pearls with exceptionally thick nacre. This creates a wonderful, deep lustrousness, and satiny character. Fine, large strands can easily exceed $400,000. A spectacular South Sea cultured pearl necklace recently sold for $800,000; it took over five years for Australian pearl producer Kailis to acquire enough fine, large, matching pearls to assemble it!
Exceptionally thick nacre results in the most lustrous and sensual pearls, but it also reduces the number of flawless surfaces and perfectly round shapes; these are extremely rare in South Sea pearl varieties. As a result, various treatments are being used increasingly to improve surface appearance and shape; and with such thick nacre, pearls can be polished to remove surface blemishes and improve both shape and lustrousness; however, in such cases the luster diminishes over time. Untreated South Sea pearls are becoming increasingly rare. Large, shimmering South Sea pearl strands selling for under $100,000 are usually treated.
There is nothing wrong with treated pearls—the popular “chocolate” pearls that recently entered the market are all treated color—but treated pearls are often sold without disclosure, at inflated prices. When purchasing—especially golden or black pearls—ask explicitly whether or not the color is natural, and in all cases, ask about treatments.
Australia was the pioneer in using Pinctada maxima oysters to produce white South Sea pearls, and many connoisseurs consider theirs the finest pearls produced today. They average 14 millimeters, but some have exceeded 20 millimeters in diameter! Shapes include symmetrical and assymetrical baroques (shapes other than round) as well as round, but perfectly round pearls are very rare and, especially in large sizes.
The leading producers of golden pearls are the Philippines and Indonesia. Color ranges from pale champagne to yellow to deep gold, and sizes from as small as 8 millimeters up to 16; those over 16 millimeters are very rare. They occur in all shapes, but perfectly round shapes are very rare. Moderate spotting on surfaces is also to be expected.
Often called “Tahitian” pearls, these exotically colored black pearls were first cultivated throughout French Polynesia; Tahiti serves as the distribution center for the area, which covers thousands of miles. The Cook Islands are also another important source, and other countries such as Vietnam are venturing into black pearl production. These pearls are produced by the Pinctada margaritifera, known as the “black-lipped” oyster (from the color of its shell lining). Another large oyster variety reaching a foot or more in size, its pearls are usually dark in color, ranging from bronze to light gray to charcoal to almost black, with wonderful overtones of green, blue in or pink playing across their dark surfaces. The average size is 13 millimeters, but in very rare cases have been known to exceed 20 millimeters! Lustrousess ranges from velvety to exceptionally intense. Moderately spotted surfaces are normal. Perfectly round or symmetrical shapes are rare, but interesting baroque shapes are very popular, particularly asymmetrical or whimsical shapes.
In recent years, efforts to produce more pearls in a shorter time resulted in declining quality. This led to use of excessive treatments and plummeting prices caused by the flood of inferior pearls into the market. Stricter controls are now in place, quality is improving and prices are strengthening.
A concentric ring encircling a pearl is a surface characteristic that can appear on any variety. A single ring is considered a surface blemish, but the presence of numerous concentric rings can create a very distinctive pearl—especially those from the South Pacific in shades of white, gray to black, and aubergine. Rings usually occur in off-round or baroque shapes and are much less rare and expensive than round pearls or symmetrical baroque shapes, but they are very popular with avante-garde jewelry designers.
These have made a splash in the fashion world because of their warm earth tones ranging from a yummy dark brown to lighter brown, copper, bronze and honey. But beware: the desirable original “chocolate” pearls were created by removing color from very black pearls to lighten them and then stabilizing the resulting color. Sizes range from 9 to approximately 17 millimeters, but those over 15 millimeters are rare. Lustrousness ranges from satiny to ball-bearing like. The basic body color is also complimented by lovely overtones of other colors as with other Tahitian pearls.
Dyed “chocolate” pearls are also in the market. These typically have a much “flatter” appearance, may change color over time, and should sell for much less. Fortunately, you can develop an eye. If the color seems too uniform—devoid of overtones of other colors—and the pearls have an overall “flat” character, they are probably dyed.
In Fiji, producers are using the same oyster used in French Polynesia and the Cook Islands, but with startlingly different results! Here, in the pristine water surrounding the atolls off the Fiji islands, the pearls produced occur in luminous shades of silver, soft yellow to vivid gold, pink to aubergine, pastel green and blue to deep green, bronze and brown. Strong peacock shades are typical and striking green overtones are often seen in the golden colors. A long cultivation period results in pearls with very thick nacre, so perfectly round pearls, symmetrical shapes, and flawless surfaces are extremely rare; minor spotting is characteristic but deep white blemishes lower the value. Baroque and “ringed” pearls are readily available. Fiji is producing some of the most beautiful pearls produced anywhere today, and are guaranteed not to be dyed, bleached, or color-enhanced.
Pearl culturing in Mexico’s Sea of Cortez (near Guaymas) is also a very bright spot, producing some of the world’s most beautiful cultured pearls. Produced by the rainbow-lipped Pteria sterna, the pearls occur in unusual colors from deep iridescent purple, rose, silvery blue, pink, and occasionally, copper, white and gold, with a striking surface iridescence. Nacre is extremely thick, resulting in intense luster on the finest. Most are semi-baroque and ringed pearls are often seen; minimal surface spotting is common. Sizes range from 5 to 14 millimeters, but round pearls over 8 millimeters are rare. No chemical processing or treatments of any type are used. “Rainbow” strands–pearls of assorted colors–in baroque shapes are in demand (round strands are very rare) and darker pearls make handsome cufflinks and men’s dress sets.
Also called “chance” pearls, these are-like natural pearls-all nacre, but accidentally produced. Saltwater oysters sometimes reject their bead implant, but particles of the accompanying mantle tissue remain and stimulate the production of nacre. Voila! The wonderful “keshi.” While some people think they should be considered “natural” pearls, they are a by-product of the culturing process and this is not technically correct.
Japanese keshi are very small, but those of greatest interest are the larger South Sea variety, from 8-10 millimeters and up. They can be found in virtually any shape including round, but most are asymmetrical baroque shapes. They also occur in virtually all shades. One of the most striking characteristics of South Sea keshi is their very intense luster and iridescence, far greater than seen in even the finest cultured pearls.
A mabé pearls is a dome-shaped pearl available in a variety of colors and shapes, the most common being white in color and round or pear-shaped. These pearls are produced very inexpensively, but they provide a very large, attractive look at an affordable price compared to other pearls of comparable size. They are more fragile than other pearls and should be worn and handled with care.
The mabe pearl is an assembled pearl produced by placing a hemisphere-shaped nucleus, usually a piece of plastic, against the side of the shell interior. The oyster then produces a nacre coating over the plastic. The resulting pearl is cut from the shell, and the plastic removed (since the nacre won't adhere to plastic). The remaining hollow nacre "blister" is then filled with epoxy, following which mother-of- pearl is attached to the back. Luster can range from very low to high; surfaces are usually cleaner than other pearls. Surface appearance is often enhanced by artificial treatment.
Mabe pearls are produced in many countries and quality differences abound. It is especially important when selecting mabe pearls to select pearls with a thick nacre coating to avoid premature chipping, peeling or cracking. The longevity of mabe pearls is usually much less than other pearls and they have little intrinsic value.
Seed pearls are very tiny, round, usually natural pearls or tiny keshi, usually under two millimeters in size. They are rare today, but often seen in antique jewelry. They are sometimes cut in half to create a larger supply for a particular piece of jewelry or to remove a blemish or misshapen side; these are called "half-pearls" and they are much less expensive than full seed pearls. Seed pearls can be produced by both freshwater and saltwater molluscs. They occur in a variety of qualities. Longevity is excellent and intrinsic value is good, although they are normally too few, and too small, to have any great value.
American freshwater cultured pearls are a different product from Chinese freshwater pearls. Like the saltwater cultured pearl, production techniques require the insertion of a shell nucleus. Quality is very fine, but far fewer pearls are produced and costs are higher than other freshwater pearls. They have a totally different appearance from all other cultivated pearls and the nacre is much thicker than most saltwater pearls cultured in Japan and China. Luster is intense with rich orient. Colors include white, silver, gray, cream, and fancy colors such as pink, peach and lavender. Round shapes are not yet available, but coin, stick, and navette shapes are available. They also produce an interesting pearl called the domé.® It resembles a mabé pearl, but they are not hollow, have thick nacre, and the pearl remains embedded within a portion of the shell that can be cut into a variety of shapes that are popular with designers. Sizes can be quite large, some fancy shapes reaching 10x40 millimeters. No artificial enhancements are used. The longevity of these pearls is excellent.