Tips of the Trade
Gloria Lieberman appraises a Tiffany neclace at 2012 ROADSHOW event in Bosston.
Tiffany & Co. Natural Pearl Necklace, ca. 1909
Diamonds dazzle; pearls glow.
Natural pearls have rings like an onion.
Both natural and cultured pearls take on "baroque" shapes.
In America, pink pearls are at a premium.
Editor's Note — 2.11.2013: Originally posted in 2002, this article takes a closeup look at the difference between natural and cultured pearls.
Before Berj Zavian, jewelry consultant to Doyle New York, explains how to distinguish between a natural pearl and a cultured one; before he tells you how to select one; before he provides pearl preservation advice; he wants you to put your pearl between your teeth. That's right, between your two front teeth. Berj does it all the time.
Natural vs. cultured—can you tell the difference? Learn more with a whole string of tips from the ROADSHOW's guru of pearls
"Customers say, 'What is he doing putting dirty pearls in his mouth?' " Berj notes. What he's doing is using his teeth to feel whether a pearl's surface is gritty, meaning it's a natural or a cultured pearl that a clam or oyster has worked on; or slippery, meaning it's a chintzy plastic imitation pearl.
Berj has been testing and playing with pearls for nearly half a century. In the 1950s, Berj designed pearled animal brooches with his father, Carney Zavian. Soon after, a Frenchman taught Berj how to "peel" pearls—the act of rubbing a new finish on a mottled or pocked pearl ("I don't teach that to anyone," says Berj says of his proprietary skill). About a quarter-century ago "a little old German woman" taught him how to string single pearls into full-length necklaces, and since that time, pearls have become the bedrock of his business.
"What can you always give a girl?" Berj asks rhetorically. Answer: "Pearls." So when it comes to pearls of wisdom about these orbed organic wonders, we knew Berj was the one to ask. Here's what he told us.
Natural vs. Cultured
Natural pearls are made when an irritant finds its way inside the shell of an oyster or clam. In response, these bivalves quarantine the intruder, whether a grain of sand or an invading worm, by coating it with a calcium carbonate substance known as nacre (pronounced nay'ker). Over time, layer after layer of nacre produces a subtly luminous, iridescent pearl. These naturally occurring pearls were the ones predominantly used in jewelry making up until the 1920s.
The Jazz Age marked the beginning of the cultured pearl era. Pearl "farmers" make cultured pearls by implanting the clam or oyster with a "seed." Pearl makers over the years have experimented with various seeds, including a glass marble, a plastic bead, or a rounded piece of pigtoe clam shell, which produces the most desirable of all cultured pearls. "It's an operation like an artificial insemination," Berj says. "You have to open them up but you can't kill them." By manipulating a clam's environment and other factors, cultured-pearl makers can alter the size, shape, color, and clarity of a pearl. Black water, for example, begets black pearls, very popular today.
Cultured-pearl growers produce marketable pearls in a year or two; natural pearls can take eight to ten years to form. Fresh and saltwater farmers all over the world mass-produce cultured pearls, which now practically monopolize the pearl market. They sell for about one tenth the price of the far rarer natural pearl. Berj notes the Chinese are now exporting 50-pearl necklaces for as low as $25. "And they're not bad," he adds.
Peering into Pearls
If Berj needs to authenticate an expensive strand of pearls as natural rather than cultured, he can't rely on a casual, cursory inspection. "By just looking at the outside of a pearl you cannot tell the difference," Berj says. "Even people in the trade make mistakes when they try to do it that way."
Instead, Berj literally looks into the pearl, the way a geologist learns about the earth by examining its layers. To do so, he relies on a tool usually found in a doctor's or dentist's office: the x-ray. If the pearl already has a hole in it for a strand to pass through, he uses a tiny fiber optic light to probe the drill hole. Peering inside, if you can see onion-skin-type layers throughout, you have a natural pearl. In cultured pearls, the large beaded center will lack layers.
Evaluating pearls need not be so high tech, however. Berj says he used to use the general store combo of a flashlight and a 10x loupe to inspect a pearl's thread hole. It's an investigation you can conduct at home whether you're trying to determine the authenticity of your great-grandmother's pearl necklace or you're introducing your grandchild to the subtleties of how bivalves produce pea-sized luminescent orbs.
If you're looking to buy pearls, remember that the rounder the pearl, the more it costs. So if you're willing to put up with, or even prefer, the vagaries of nature, buy irregularly shaped pearls with blemishes, called "baroque" pearls. They were popular in the early Renaissance and are used today to make unusual figural pins. White and pink pearls are more expensive than creamier ones, and a walnut-sized pearl will cost you more than tapioca-sized ones.
Whatever your choice, remember that one of the biggest threats to a cultured pearl is an overzealous cleaner. Pearls, like all jewelry, get dirty after repeated wearings. Unfortunately, misguided pearl owners often scrub them with an abrasive.
"When you use an abrasive you take part of the surface away," Berj explains, noting that it's easy to erode a cultured pearl down to its unnatural center (with a string of pearls, a knot is tied between each pearl to keep them from scratching one another). Berj suggests treating your pearls with all the gentleness they deserve. In the case of cleaning, the simplest solution is the best. "Just wash them in soap and warm water," Berj advises.
More ANTIQUES ROADSHOW articles from the Jewelry category:
Seed Pearl Jewelry (Tampa, 2006)
Ancient Beauties: Collecting Cameos
Authenticating Gold and Diamonds
American Gypsy Jewelry
Gazing Into Lovers' Eyes
Dennis Gaffney is a freelance writer in Albany, New York. He has been a regular contributor to ANTIQUES ROADSHOW Online since 1998.