American Gem Society
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Natural and Cultured Pearls

Virtually all pearls offered for sale are cultured pearls. Natural pearls, historically found in the waters of the Mediterranean Sea, especially in and around the Middle East, and to a lesser extent in the waters off Central and South America, havePearls long since become extinct through over-fishing and pollution. "Culturing" pearls, a process whereby a nucleus bead, usually of shell, is implanted within an oyster which then deposits layers of nacre around the irritant, was first made commercially successful by S. Mikimoto in Japan around the end of the 19th Century. Today, pearls are cultured around the world with the most successful producers located in Japan, China, Australia, and French Polynesia.

But fine cultured pearls are rare. According to the Cultured Pearl Association of America and Japan, less than 50% of nucleated oysters actually produce a pearl, and of these, only about 20% produce pearls which are commercially marketable. Furthermore, less than 5% of these qualify as "gem" quality, the highest quality available. These small supplies can be further reduced by pollution and disease.

Types of Cultured Pearls

1. Akoya - The name refers to the mollusk in which these pearls grow. The most popular and widely available of the cultured pearls, they are produced mainly in Japan and China and average under 10 millimeters in diameter. Typical colors of these pearls range from pink to cream with some occurring in other colors.

2. South Sea - Larger than Akoyas, these pearls average over 10 millimeters in diameter and are found in the tropical and semi-tropical South Sea waters around Australia. Their typical colors range from silvery white to gold. It frequently takes several years of harvests to accumulate enough pearls for a higher quality matched strand of South Sea cultured pearls.

3. Tahitian Black - Like South Sea pearls, these average over 10 millimeters in diameter. They are produced by the black-lipped oyster in the South Pacific in and around French Polynesia. Their typical colors range from silvery-gray and green to deep purple-black. Like South Seas, matched higher quality strands of these pearls may require several years of harvests to accumulate.

4. Mabe - These hemispherical pearls are grown against the inside shells of the oysters rather than in their bodies, and are typically filled and backed. They are more affordable than Akoyas, South Sea, and Tahitian Blacks and are popular in ear clips, necklace enhancers, and brooches.

5. Freshwater - Freshwater cultured pearls are grown in mussels, not oysters, and come in a variety of pleasing free-form shapes. True Biwa pearls (from Lake Biwa in Japan) are probably the most famous of the freshwater pearls. These have become increasingly rare in recent years due to over fishing and pollution. Major sources of freshwater pearls are rivers and freshwater lakes in China, Japan, and the Unites States. Because freshwater pearls are relatively easy to cultivate in large numbers, they are much more affordable than most of the other types of cultured pearls.

6. Keshi - Also called "seed pearls", Keshi are very small pearls that form accidentally in many of the oysters nucleated for cultured pearl production. Keshi pearls can occur in South Sea and Tahitian oysters as well as Akoyas. Tahitian Black Keshi are relatively new on the market and come in a variety of remarkably vivid colors.

7. Baroque - Irregularly shaped cultured pearls, usually Akoyas, Baroque pearls can be very colorful and lustrous. Because their free-form shapes are far more plentiful than spherical pearls, they are much more affordable than rounds and semi-rounds.

Types Of Cultured Pearl Necklaces

1. Choker - A single strand 14 to 16 inches in length. The Choker is designed to rest on the collarbone.

2. Princess - A single strand 17 to 19 inches in length.

3. Matinee - A single strand 20 to 24 inches in length.

4. Opera - A single strand 28 to 36 inches in length. Normally, an Opera should fall below the bust line.

5. Rope - Any single strand longer than an Opera (sometimes called a Sautoir). Ropes can worn with shorteners, twisted, or knotted.

6. Dog Collar - A multiple strand necklace that fits closely around the neck.

7. Bib - A necklace of multiple strands of varying lengths so that the shorter strands fits higher around the neck than the longer strands.

8. Torsade - A necklace of multiple strands twisted together and held with a special clasp. The most common type of Torsade is made with freshwater pearls.

9. Graduated - A strand of pearls of gradually increasing size in which the largest pearl is at the center and the smallest pearls are at the ends.

10. Uniform - A strand of pearls of approximately the same size. There may be a slight difference in size between the center and end pearls.

Care And Cleaning Of Cultured Pearls

Because cultured pearls are softer than many other gems, they should be stored in a soft fabric bag or tissue and kept away from other jewelry. Diamonds, rubies and sapphires can scratch and abrade pearls. Also, keep pearls away from hair spray, abrasives (which includes many cosmetics), and household cleaners. Try applying hair spray and cosmetics before putting on your pearls. When removing the pearls, wipe them with a soft damp cloth. Pearls strands should be kept dry because moisture may causes the silk string to stretch, loosening the pearls. If your strand should get wet, lay it on a flat surface, blot it with a soft cloth, and allow it to dry before wearing again.

Cultured Pearl Enhancements And Treatments

Pearl treatments have been traced back as far as A.D. 400 when it was believed that if the pearls were swallowed by chickens, their luster could be improved. Today, virtually all cultured pearls are treated in some way to improve their appearance. The most widely used treatments are:

1. Bleaching - Virtually all cultured pearls are bleached to improve color and allow better matching of strands.

2. Tumbling - Virtually all cultured pearls are polished in tumblers to make them more round and lustrous. Tumblers, as the name implies, tumble a number of pearls together, allowing them to polish one another.

3. Dyeing - Cultured pearls may be dyed in some of the black, grayish-blue, pinks, and golden hues. Dyed pearls must be disclosed by the seller to the buyer at the time of sale. Dyed black and golden pearls should be distinguished from Tahitian Black and South Sea Golden pearls.

Buying Cultured Pearls

Don't buy cultured pearls on name recognition alone. A major name doesn't necessarily mean better quality. Buy on value - the best quality at the best price. Cultured pearl quality is determined by five major criteria: luster, color, shape, surface condition, and size. When evaluating a strand of pearls, matching of quality is also important.

1. Luster - This quality refers to the pearl surface's ability to reflect light. It is a combination of surface brilliance and a glow emanating from deep within the pearl nacre. The finest pearls have a bright, almost metallic luster. This high luster is a result of a heavier layer of nacre deposited by the oyster in a process that can take up to 3 years. Pearls harvested too soon, by growers interested in a quick profit, will have a very thin layer of nacre, giving the pearl a dull, chalky appearance.

2. Color - Cultured pearls come in a variety of colors from pinks to blacks. Although personal preference should play an important role, usually pink colors are more flattering to fair complexions, while cream and golden colors are more flattering to other skin tones. Pink and silver-white colors generally command the highest prices.

3. Shape - Pearls come in a variety of shapes. Perfectly round cultured pearls are very rare. Round and semi-round shapes are the highest priced and the more common free-form baroques will be less expensive.

4. Surface - Due to the natural growth of their nacre, most cultured pearls exhibit some types of blemishes. Most common are pits, spots, bumps, and small surface cracks. The fewer blemishes a pearls contains, the higher its value.

5. Size - Pearls are measured by diameter in millimeters. Sizes range from under 1 millimeter in seed pearls to as large as 20 millimeters in South Sea cultured pearls. All other factors being equal, the larger a pearl, the greater its value. Worldwide, the most popular size of cultured pearl is 7 to 7 1/2 millimeters.

6. Matching - When selecting a strand of pearls, it is important that they be properly matched in luster, color, shape, surface condition, and size. Generally, the closer the matching, the higher the value of the strand.

The Gleim Collection

Gleim's carries a large selection of Akoya, Tahitian Black, and South Sea White and Golden pearls, all at exceptional values. We also carry pearl clasps and necklace enhancers. And we offer a complete restringing service to help you get your pearls back in shape. Come visit us and see the difference a fine selection can make.




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