When buying cultured pearls, consumers must consider several quality characteristics that are very different from the “four C’s” of diamonds or gemstones.

Nacre quality is very important. The nacre is the layers of protective coating — a pearly substance — that grows around a pearl nucleus. Experts warn that only pearls with a sufficient layer of nacre will last through years of wear; thin-nacre pearls often peel or crack. A nacre that is less than 0.35 mm is considered too thin, and thicker is always better. Nacre thickness can be measured by X-ray or by examining the drill hole to see how far the hole goes before reaching the bead at the center.

Here are some other pearl quality considerations for buying pearls:


Luster is described as the combination of surface brilliance and a deep, three-dimensional glow. This glow is the light that is reflected, not only off the pearl surface, but off the internal layers of nacre. In fact, the luster of a pearl depends on the quality of its nacre — its transparency, thickness, and smoothness. High-luster pearls have a mirror-like finish that is bright and not dull. They command much higher prices than pearls with a low luster. Low-luster (and therefore low-quality) pearls appear chalky or dull with a flat finish.

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A pearl’s surface is considered “clean” when it’s free of organic spots, bumps, or indentations. Generally speaking, the cleaner the pearl, the more valuable it is. It is normal for pearls to have some flaws, like small scratches or bumps, but buyers should avoid pearls with cracks or chips, as they will only get larger over time. Look for such damaging blemishes near the drill hole of a pearl. Obvious discoloration, patches of missing nacre, and blemishes covering the majority of the surface of the pearl are other things to look out for — and avoid.


Round pearls have long been considered the best quality — or at least have been the most popular, commanding the highest prices. But in recent years, pearl shape has become more a matter of taste than of quality. Many people enjoy oval or drop-shaped pearls. Asymmetrical or baroque pearls also have a unique charm at a more moderate price than rounds. Keep in mind, also, that since cultured pearls are grown by oysters and subject to the whims of Mother Nature, it is rare to find a pearl that is perfectly round.


Cultured pearls occur in a variety of colors from white to black and just about every color in between. Color is not usually a true indicator of pearl quality, although certain colors command premium prices. The choice of color should be determined by the buyer’s personal preference or taste. The range of pearl hues can complement the wearer’s hair, skin, and eye color; buyers should choose what looks good on them.

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Generally the larger the pearl, the more valuable it will be. Sizes of cultured pearls range from 1 mm for a very tiny keshi pearl to as large as 24 mm for a baroque South Sea cultured pearl. The average size pearl is about 7 mm. Size dramatically affect prices, especially for pearls over 7 mm.

Buyers are encouraged to consider all of the pearl quality criteria before choosing the pearls they wish to purchase. It is important to note that even a pearl that is almost perfectly round and blemish-free is not considered high quality if it has a low luster or a thin nacre.

Imitation Pearls

There are several types of imitation pearls, including:

  1. Hollow glass beads containing wax
  2. Solid glass beads
  3. Plastic beads
  4. Mother-of-pearl shell beads

These imitation pearls are usually coated with something to give them a pearly appearance, such as pearl essence, powdered mother-of-pearl and synthetic resin, synthetic pearl essence, plastic, cellulose, and lacquer.

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Are They Real or Fake?

Here are a few tips and tests that may help you figure out whether your pearls are real (meaning cultured or natural). Experts recommend using several of these tests on your pearls to best help in ruling out the possibility of fakes. No one test is fool proof, and certain tests are less effective with different types of pearls.

Tooth test:
rub pearl lightly across upper front teeth
feels gritty or sandyfeels smooth
Magnification test:
examine pearl surface with a loupe
appears unusually fine-grainedappears grainy
Drill hole test:
examine the drill hole area with a loupe
edges are smooth and sharpholes are bumpy or ragged
Heaviness test:
bounce pearls in your hand
feels heavy to holdfeels unusually light (unless they are solid glass beads)
Flaw test:
examine pearls for flaws and blemishes
most will have at least minimal flawsif they appear absolutely flawless they are most likely fake
Price test:
compare price to similar pearls from other dealers
has reasonable or comparative priceprice is unbelievably low or discounted