Gems Log

A strand of pearls might be an old standard, but this classic accessory isn’t just for dressy occasions anymore. It’s time to dig out those strands your grandmother passed down to you, or, if your jewelry box is lacking pearls, it’s time to start shopping.

Just as there are classic pieces necessary for a pulled-together wardrobe, there should be a strand of pearls in every jewelry box.

And don’t worry about looking matronly — these days, pearls go with just about anything. A simple pair of post earrings or a dainty pearl bracelet works for everyday wear, and when it’s time for a more glamorous look, cascading pearls or even chandelier pearl earrings are both lovely and in vogue.

Still, the most popular pearl jewelry might be the single strand.

Many black pearls have been dyed. Jewelry author Renee Newman notes in her book “The Pearl Buying Guide” (International Jewelry Publications, $19.95) that dyed black pearls have been sold in fashionable stores as far back as the 1930s — long before black pearls were being commercially cultivated. “Dyed black pearls were considered elegant,” Newman writes.

Pearls signify purity — making them a traditional gift for brides, too — and giving each woman in the bridal party a necklace ties the group together with an accent piece that can be worn long after the dresses are stored away.

Pearl quality

There is no standardized system for grading pearl quality. But whether you’re looking for pearls to wear on your wedding day or for any day of the week, experts say there are several factors to consider when shopping:

• Avoid chalky-looking pearls that have a thin coating. Quality pearls are lustrous, so look for luster first.

One way to judge luster is to look for the “eye” (the point where the light reflects off the pearl). The deeper that eye is within the pearl’s surface, the higher the luster.

The best quality pearl has a luster that reaches around the pearl. A pearl that looks flat and grainy with an eye on the surface has a lower luster.

• Place the pearls on a white background to judge their true color. Other background colors could distort their true color. But, even white pearls come in shades of pink, gold, blue or green.

Today there are three main categories of pearls: Chinese freshwaters, Akoyas and South Sea.

• Chinese freshwaters are the least expensive and most common. They are cultured pearls (not naturally occurring) and come in round and other shapes.

• Akoyas are relatively expensive, pure white and perfectly round with a standard diameter of 7 millimeters.

• South Sea pearls come only in large sizes — 10 millimeters or more. To save money, buy baroque (irregularly shaped) South Sea pearls.

Know how to shop and care for pearls

Caring for your pearls

The American Gem Society reminds us that pearls, like all fine jewelry, require special care.

Pearls are exceptionally soft compared with other gems, so when they’re stored, they should be separated into their own cotton or silk pouch.

Chemicals present in hairspray or cosmetics can damage cultured pearls, so wait until you’re dressed and ready before putting them on. After wearing, wipe them with a soft cloth to remove your skin’s oils and salts.

Pearls might need to be restrung periodically to protect against breakage and possible loss.

How to clean pearls

In “Pearl Buying Guide,” author Renee Newman offers these tips for cleaning pearls (International Jewelry Publications, $19.95):

• Don’t use commercial jewelry cleaners on pearls unless the label says it’s safe for pearls. Many contain ammonia, which can damage pearls.
• Don’t clean pearls in an ultrasonic cleaner. It can damage them or even wash out the color in dyed pearls.
• Never steam-clean pearls as they can be harmed by heat.
• Don’t use detergents, bleaches, powdered cleansers or baking soda on pearls. Ditto with any abrasive material, such as a toothbrush or scouring pad, that can scratch their surface.
• Use a soft cloth or chamois to wipe pearls. That will prevent dirt from accumulating and keep perspiration, which is slightly acidic, from eating away at the pearl nacre.
• If they’re very dirty, pearls can be washed in water with a mild soap such as Ivory or Lux liquid. (But some liquid soaps, such as Dawn, can damage pearls.) After washing, lay the pearls in a moist kitchen towel to dry. When the towel is dry, they should be dry.

Do not wear pearls when their string is wet. Wet strings stretch and attract dirt, which is hard to remove.

Pearls in jewelry

The value of the pearls in jewelry is determined by a combination of the luster, color, size, lack of surface flaw and symmetry that are appropriate for the type of pearl under consideration. Among those attributes, luster is the most important differentiator of pearl quality according to jewelers. All factors being equal, however, the larger the pearl the more valuable it is. Large, perfectly round pearls are rare and highly valued. Teardrop-shaped pearls are often used in pendants.

Pearls come in eight basic shapes: round, semi-round, button, drop, pear, oval, baroque, and circled. Perfectly round pearls are the rarest and most valuable shape. Semi-rounds are also used in necklaces or in pieces where the shape of the pearl can be disguised to look like it is a perfectly round pearl. Button pearls are like a slightly flattened round pearl and can also make a necklace, but are more often used in single pendants or earrings where the back half of the pearl is covered, making it look like a larger, round pearl.

Drop and pear shaped pearls are sometimes referred to as teardrop pearls and are most often seen in earrings, pendants, or as a center pearl in a necklace. Baroque pearls have a different appeal to them than more standard shapes because they are often highly irregular and make unique and interesting shapes. They are also commonly seen in necklaces. Circled pearls are characterized by concentric ridges, or rings, around the body of the pearl.

In general, cultured pearls are less valuable than natural pearls, and imitation pearls are less valuable than cultured pearls. One way that jewelers can determine whether a pearl is cultivated or natural is to have a gem lab perform an x-ray of the pearl. If the x-ray reveals a nucleus, the pearl is likely a bead-nucleated saltwater pearl. If no nucleus is present, but irregular and small dark inner spots indicating a cavity are visible, combined with concentric rings of organic substance, the pearl is likely a cultured freshwater. Cultured freshwater pearls can often be confused for natural pearls which present as homogeneous pictures which continuously darken toward the surface of the pearl. Natural pearls will often show larger cavities where organic matter has dried out and decomposed.

Some imitation pearls are simply made of mother-of-pearl, coral or conch, while others are made from glass and are coated with a solution containing fish scales called essence d’Orient. Although imitation pearls look the part, they do not have the same weight or smoothness as real pearls, and their luster will also dim greatly.

There is also a unique way of naming pearl necklaces. While most other necklaces are simply referred to by their physical measurement, strings of pearls have their own set of names that characterize the pearls based on where they hang when worn around the neck. A collar will sit directly against the throat and not hang down the neck at all; they are often made up of multiple strands of pearls. Pearl chokers nestle just at the base of the neck. The size called a princess comes down to or just below the collarbone. A matinee of pearls falls just above the breasts. An opera will be long enough to reach the breastbone or sternum of the wearer, and longer still, a pearl rope is any length that falls down farther than an opera.

Necklaces can also be classified as uniform, or graduated. In a uniform strand of pearls, all pearls are classified as the same size, but actually fall in a range. A uniform strand of akoya pearls, for example, will measure within 0.5 mm. So a strand will never be 7 mm, but will be 6.5-7 mm. Freshwater pearls, Tahitian pearls, and South Sea pearls all measure to a full millimeter when considered uniform. A graduated strand of pearls most often has at least 3 mm of differentiation from the ends to the center of the necklace. Popularized in the 1950s by the GIs bringing strands of cultured akoya pearls home from Japan, the graduated style was much more affordable as most pearls in any given strand were small.

Earrings and necklaces can also be classified on the grade of the color of the pearl. While white and more recently black pearls are by far the most popular colors other tinges of color can be found on pearls. Pink, blue, champagne, green and even purple can be found, but to form a complete string of same size and shade pearls can take years. Some colors like purple can only be found in certain types of clams, while other clams can produce a variety of colors if given the right environment.