Pearls: How To Spot The Real Deal - ABC News

Nov. 28 -- Diamonds may be a girl's best friend, but thousands of women still lust for the timeless elegance and glamour of pearls.

But can you tell a top-of-the-line strand from a second-rate — or a just plain fake — one? Experts say most of us probably can't.

"There is no way a lay person can tell," says Cos Altobelli, an expert gemologist and appraisals chairman for the American Gem Society. "You have to depend on someone who sounds knowledgeable."

Pearls are the only precious gems that are produced by a living creature. Most pearls on the market today are cultured, which means they are made at an oyster farm by inserting a small piece of shell into an oyster. The oyster then secretes a silky coating around the irritant — layer by layer — until a pearl is formed. The quality of cultured pearls varies widely.

What You Should Know

So how do you know the truly valuable from the second-rate? Here are some tips:

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•Color: Though white is often preferred by people with fair skin, the most valuable pearls are white with a rose overtone. Some complexions may look better with cream-color pearls, which are also less expensive than rose ones.

•Surface thickness: Also important is the thickness of the nacre, the substance that is deposited on the bead when it is placed in an oyster. A thick nacre is best. To test it, Altobelli suggests holding a strand of pearls next to a bright light and rolling the pearls. "If they have a thin nacre, the pearls will blink at you," he says. "This has two resulting effects: poor luster, and if you wore them every day for a fair length of time, it would wear through the nacre."

•Luster: "It is what gives a pearl a striking appearance rather than being pale or uninteresting," says Altobelli. The thicker the nacre, he explains, the better the luster.

•Shape: Perfectly round pearls are the most coveted. Baroque or semi-baroque shaped pearls, meaning slightly out of round to substantially out of round, can be relatively inexpensive. If you roll pearls on a flat surface, you can see if they are slightly elliptical or not quite perfectly round.