• Obvious discolorations throughout the pearls. For the sake of beauty, try to select pearls with a uniform color. There are plenty of them available.

• Blemishes which cover the majority of the surface of the pearl. They can cause a viewer's attention to be directed more at the blemishes than at the pearls.

Despite the undesirability of blemishes, if you had to choose between heavily flawed, lustrous pearls and near flawless pearls with very thin nacre and low luster, you would be better off with the flawed ones. At least you would be getting some pearl for your money.

Keep in mind when buying pearls that it's not just their inherent quality that determines their acceptability. Your needs and desires also count. If you're looking for a fine quality necklace, you'll want to avoid strands with noticeable flaws. If your budget is limited, you'll probably be glad that there are blemished pearls available at reduced prices. You have the final say as to what's acceptable and what's not.

Tips On Judging Surface Quality

When you shop for diamonds, salespeople may suggest that you look at the stone under magnification so you'll know its clarity. This won't happen when you shop for pearls. The reason jewelers don't have you view them under a microscope is because pearls are graded and valued on the basis of how they look to the naked eye, not under magnification (except nacre thickness).

When dealing with knowledgeable salespeople who have your interests at heart, you won't have to look at pearls with a loupe (hand magnifier). They will point out the imperfections and other quality factors and show you how to compare pearls. But there are times when it is advisable to use a loupe: • When dealing with people you don't know or who may not be trustworthy. Suppose you are at a flea market or an antique show and you see a pearl piece you'd love to have that you would never find in a jewelry store. Or, suppose you are on vacation abroad and you want a souvenir but you don't know any jewelers and none have been recommended to you. In both cases, it would be advisable to use a loupe and check for flaws, thin nacre, dye and imitations. The more experienced you become at examining a pearl's surface and drill holes with a loupe, the easier it will be for you to identify pearls and judge their quality.

• When the lighting is poor. Suppose you're an antique dealer or a pawnbroker and you're in a place where the lighting is not ideal. And suppose you have to make a quick decision about whether to buy some pearls and how much to offer. Poor lighting will make it harder to judge surface quality and detect imitations. Use a loupe as a means of compensating for the lack of proper lighting.

• Whenever pearls are being offered at a price that seems too good to be true. There's usually a catch somewhere. It will probably be easier to find it with a loupe than with the unaided eye, especially for people who don't deal with pearls on a regular basis.

A few other pointers for judging imperfections are listed below:

• Besides looking at the pearls against a white background, look at them against a dark one. Certain flaws show up better against black or other dark colors. Also hold the pearls in the air to examine them for flaws. Do not judge luster or color in this way, however.

•   Examine the pearls under a strong light. The more intense the light, the easier it is to see detail. When judging blemish, it's also a good idea to look at pearls under different types of lighting-bare/diffused, fluorescent/ incandescent, close/distant. Each type may bring out different details in the pearls.