Chinese Freshwater Cultured Pearls

Jewel of the Month? “Jewel of the Year” may be a better title for Chinese freshwater cultured pearls (CFWCP). The last three years have seen a strong pearl market, and Chinese freshwaters have led the way.

History and romance. Natural pearls have adorned men and women for thousands of years. Royalty used ropes of natural pearls to decorate their uniforms of wealth and power. Homes were decorated with pearls, from chairs to doors, tables to lamps. According to legend, Venus, the goddess of love, favored the pearl, so pearls were ground up and sprinkled generously into love potions. Not knowing that the pearl’s luster was affected by acidic perspiration and perfumes, a dull pearl was thought to be an indication that the wearer was in poor health. Ground pearls were then used as medicines to combat such afflictions.

Nothing illustrates the historical value of natural pearls like the story of the infamous Cartier necklace. It is said that in 1917, after most known natural pearl sources had been exhausted, Cartier traded a million-dollar strand of natural pearls for what would become its New York City headquarters, a six-story mansion in Manhattan.

The culturing of pearls may have originated in China in the 13th century in the form of Buddha-shaped blister pearls. A farmer would implant a small sculpture of Buddha on the inside of the freshwater shell, and the mussel would grow a nacreous covering to create the pearly Buddha image. In the late 1800s, Japan’s Mikimoto helped promote the growth of round cultured pearls by inserting a round mother-of-pearl bead into the body of a saltwater pearl oyster. A thin layer of naturally produced nacre laid over the bead created the spherical cultured pearl. By the middle of the 20th century, the Chinese also were creating cultured freshwater pearls, but instead of a bead nucleus, a tiny piece of mantle tissue was used to stimulate pearl growth. Layers of natural nacre induced by the small piece of tissue created what are now referred to as “Rice Krispie-shaped” pearls. Thus, these freshwater pearls are mostly all nacre, which is probably as close to the natural pearl make-up as one can get. Today, the Chinese are getting even better results with mantle tissue nucleation, and they’re now creating big, spherical, beautiful freshwater pearls.

Recent debate over the type of nucleus used to grow these pearls has dominated and possibly overshadowed this accomplishment. For the most part, small pieces of mantle tissue have been used as the catalyst, and 95% or more of the pearl is natural nacre. There are bead-nucleated freshwater pearls-made from mother-of-pearl, old “ground-to-round” freshwater cultured pearls, or other bead materials-but their numbers are few compared with the 1,000 tons of mantle tissue-nucleated cultured pearls found annually on the market.

Qualities. As with any pearl, the quality factors are luster and surface marks. Luster is the pearl’s ability to reflect light. While it may have been true in years past that the luster of a pearl was left completely up to nature, today’s pearls are tumble-polished to give the surface its best appearance, just as a flat facet is polished to give the gem surface a higher luster. Older, more traditional methods of polishing involved tumbling the beads in tree bark or bamboo chips. Modern techniques include tumbling in diamond grit, the same material used to polish or facet gem calcite or gem aragonite, the two minerals that make up nacre. The better the polish, the higher the luster.

Surface marks or blemishes can result from natural growth or damage. The smoother and cleaner the surface, the higher the quality of the pearl. Bumps, flats, and wrinkles are among the marks produced by nature. The fine-quality CFWCPs have few if any of these marks. Other types of blemishes-such as scratches, cracks, and chips-are commonly caused by consumer wear.

Color variations. The trade sees mostly “spice colors”-peachy or cinnamon colored pearls. In addition, there are bright pastel pinks, purples, and golds as well as creams that fade into almost pure whites. There also are grays that approach the lighter Tahitian gray colors but nothing yet to compete with the true blacks.

Value. There are seven value factors. These include the two quality factors (luster and surface marks) along with size (the bigger the better), shape (round is best), color (a matter of personal taste), matching (the better the match, the more a pair or set will cost), and nacre thickness (thickness is good). The CFWCPs are reaching 11-12 mm in rounds, and there are reports that even bigger pearls are on the way. With pearls this large, the CFWCPs can pick up where Japanese 7-mm and 8-mm cultured akoya pearls leave off. They can also try to approach South Seas-size pearls and may end up competing with these as well.

Most of the round CFWCPs are more “near round” than “round,” but you can bet that with the value of rounds greater than near rounds, there most likely will be an increase in production to achieve more rounds.

Nacre thickness is generally a quality factor for bead-nucleated pearls. Since almost all of a CFWCP is nacre, thickness is not a quality concern, but rather a positive factor in the value of these extraordinary cultured pearls.

Enhancements. As with nucleation debates, there has been controversy over enhancements to these pearls. CFWCPs have been said to be waxed, dyed, and irradiated, but so far, those that have been examined closely by professional labs have shown natural colors, and surfaces-which may seem unusually high in luster-are not commonly enhanced.

Pricing. Prices of CFWCPs are low considering that they’re the cultured equivalent of a large natural pearl, with high luster, a variety of colors, and nearly spherical shape. To some, however, because of the huge production numbers, the prices seem too high. But most dealers will tell you that fine top-quality pearls are still difficult to find.

Because of demand and numerous suppliers, current prices are still trying to find a general consensus. But, as an example, a strand of 8-mm to 8.5-mm good- to fine-quality multicolored rounds could range anywhere from $600 to $1,400.

Care and cleaning. Like that of all pearls, the nacre of CFWCPs is a soft material that can be damaged by hard wear as well as by the acids in perspiration and perfumes. Hair sprays can be damaging as well. Pearls should not be cleaned with jewelry cleaner; use only warm water and mild soap, and clean only when absolutely necessary. If strands are cleaned, the wet string can stretch, so let it dry completely before attempting to wear it. When the string becomes dirty, it will be necessary to re-string the necklace.

Bench precautions. Bench jewelers should be aware of the fragile nature of pearls and make every effort to remove pearls from jewelry before doing repairs.

Recommended reading. For more information, see the following references:

GIA’s Pearl Course

Kenneth Scarratt, Thomas Moses, and Shigeru Akamatsu, “Characteristics of Nuclei in Chinese Freshwater Cultured Pearls,” Gems & Gemology, Summer 2000, pp. 98-109.