The ABC's of Pearl
There's no gemstone quite like the pearl. Treasured throughout the ages, pearls are now more available than ever before.
Most commonly thought of as round and white, the pearl actually comes in a wide array of shapes and colors including cream, pink, peach, gold, blue-gray, black and a spice rack of shades from cinnamon to sage to paprika. The color of a pearl is actually a mix of its body color and overtone color or orient (the color that is seen as reflected by a diffused light source).Pearl is considered an "organic" gem because it is not mined from the earth but rather grown in a living creature. A pearl is formed when, in response to an irritant within its shell, certain types of saltwater oyster or freshwater mollusk secrete layers of a substance known as nacre--a smooth coating of mother-of-pearl-around the foreign object. In natural pearls, which are very rare, this irritant is most likely a parasite or a grain of sand.
Most pearls sold today, however, are cultured: A skilled technician implants a shell bead in a saltwater oyster or a small piece of shell mantle-tissue in a freshwater mollusk as an irritant. In essence, humans prod the natural process. Shells are left in the water to cultivate a pearl anywhere from six months to two or three years depending on the pearl type and quality desired. While pearl farmers care for the mother shells they cannot control whether the oysters will accept or reject the implanted nucleus, the precise quality produced, or natural disasters which may affect a crop.
Generally, the thicker the nacre, the better the pearl. Nacre is composed of microscopic crystals that are perfectly aligned so that light passing along the axis of one is reflected and refracted by the others to produce a rainbow glow. On the Mohs scale of hardness, pearls rank 2.5-4.5, but are fairly resilient due to their compact, concentrically layered structure of organic substances. Mainly produced in Japan, China, the South Pacific and the United States, these gems are available in several saltwater and freshwater pearl varieties.
Natural pearls--which were predominantly found in Ceylon, Scotland, Norway, and especially the Persian Gulf--were so treasured by humans that their sources throughout the centuries were exhausted. By the turn of the 20th century, the world supply of fine, natural pearls had significantly dwindled as a result of the depletion of the oyster population from over-fishing. Industrialization, the discovery of oil in the Persian Gulf and pollution contributed to its further decline.
It was around this critical time that an Australian and three Japanese inventors discovered techniques for culturing pearls. One of these inventors, the son of a noodle maker, Kokichi Mikimoto, patented one of the techniques in 1916 and was selling round cultured pearls worldwide by 1920.
Japan and its Akoya cultured pearl ruled the market for a good portion of the 20th century. But the quintessential image of a pearl as perfectly white and round is currently evolving into a vast array of colors and shapes. Never before in the long and lustrous history of pearls has there been such unsurpassed variety of pearls as is now available. In the last 30 years, China, Australia, Tahiti and other South Pacific areas, as well as America, have aggressively entered the market with their cultured pearls.
Japanese Akoya pearls are still considered among the best pearls in the world. Fine Japanese Akoya pearls are more perfectly round than most other pearls and posses very high luster and rich orient. Born of the saltwater oyster Pinctada fucata, Akoya pearls are produced in sizes from 3mm-10mm, in round, symmetrical and baroque shapes. Akoya pearls are also grown in China. For the past decade, Chinese pearl farmers have made great strides in their pearl culturing techniques. But according to dealers, the best Chinese Akoya is comparable to medium-quality Japanese in luster, orient, color and shape.
Disease has recently ravaged Japan's pearl crops, however, temporarily decreasing the availability of fine qualities and certain sizes (6mm-8mm) which has, in affect, increased prices for these products by at least some 10%.
Today, other saltwater varieties are produced in the South Pacific. Australia, Indonesia and the Philippines grow large white, cream and golden South Sea pearls in 10mm-16mm sizes, sometimes reaching 20mm. Born of the saltwater oyster Pinctada maxima, these South Sea beauties are among the world's largest most lustrous and sometimes most expensive pearls in the world. They are produced in round, semi-round, circle, drop, oval, button and baroque shapes.
Tahiti, the Cook Islands and various other areas of French Polynesia produce black South Sea pearls. Born in the black-lipped saltwater oyster Pinctada margaritifera, these naturally colored black beauties are produced in sizes from 8mm to 14mm, sometimes reaching 20mm, in various shapes. They range in tones from gray and blue-gray to brown-black and greenish black. The most expensive color is black with an iridescent peacock-green overtone.
Freshwater pearls are also causing quite a stir on today's market. China is the largest cultivator of freshwater pearls in 3mm - 10mm sizes and baroque to round shapes. Born of the freshwater mussel Uniondae hyriopsis schlegeli, these gems come in a spice rack of natural colors including plum, lavender, peach, apricot, curry, red pepper, cinnamon, celery and sage. They are durable, have a thick nacre and nice luster and come in colors not naturally found in any other pearl type, for very affordable prices.
Fine quality freshwater pearls are also grown in America in the Tennessee River in an array of sizes and fancy shapes including marquise, cabochon, coin, bar, flat drop and triangle. Colors range from pink rose to a silver steel blue often compared to the freshwater pearls that once thrived in Japan's Lake Biwa.
There are subtle differences in appearance, however, between freshwater and saltwater pearls, according to dealers. It has to do with the chemical composition of the nacres. Thick nacre does not always guarantee a lustrous pearl. Good quality Akoya and South Sea pearls have a play of color you don't see in round freshwater. Baroque freshwater pearls, on the other hand, give off a rainbow effect because the bends in the pearl serve as prisms.
There are other pearl culturing projects around the world. New Zealand, for example, is currently making a name for itself by culturing abalone mabe (hemispherical or half circle) pearls. Produced in sizes from 7mm-9.5mm to 16.5mm-20mm, these lustrous pearls come in a range of natural colors from pastel green to vibrant azure. The culturing of these pearls, grown in on-shore farms, is quite a feat considering how mobile abalones are. They cannot be contained or maintained like oysters or mussels that hang in nets in water during cultivation.
Pearls are softer than gems and require care. After each wearing, wipe your pearls with a soft, damp cloth. Mild soapy water is also fine. Do not put pearls in mechanical cleaners, heat or chemicals. Avoid contact with cosmetics, hairsprays, perfume and household cleaners to protect the integrity of the nacre. Restring pearl necklaces at least every two years, annually with frequent wearing. And never store pearls in a pile in a jewelry box: Wrap them in velvet, paper or silk.
It is important to buy fine natural or cultured pearls from a reputable retailer who will provide, in writing, all pertinent information regarding the gem including enhancements and special care notes.
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