Cultured pearls are beautiful and valued for their unique shapes and individually formed quality. However, because no two cultured pearls are exactly alike, their quality can be harder to judge. When you are evaluating the quality of cultured pearls, you must examine them closely to determine if an atypical shape or mark is simply a distinguishing aspect or an actual flaw in the pearl. Because cultured pearls are formed in the same manner as natural pearls--by irritating an oyster with a grain of sand--they have a beauty, radiance and depth that belies their engineered beginnings. While it is best to get an opinion from a qualified jeweler before investing in pearls, you can get an idea about the quality of cultured pearls using the following guidelines.

Step 1

You can see that these pearls have a very high lustre from the way that they shine and reflect light

Look for your reflection. A pearl's ability to reflect light is called its lustre. Pearls of a very high quality will actually show your reflection in their curved surfaces, while low quality and fake pearls tend to have a flat, chalky white appearance that does not emit any shine. The shinier the pearl and the clearer the reflection, the more valuable that gem is likely to be.

Step 2

Examine the surface. Since pearls are formed by a natural process inside an oyster, it is very difficult to find a flawless pearl. Most pearls have some surface discolorations, bumps or pits in their surfaces. You can feel or see these anomalies by holding the pearls or examining them under a microscope or magnifying glass. The fewer surface flaws, the more valuable the pearl.

Step 3

Evaluate the shape. The rounder the pearl, the more valuable it is. However, if you find that your pearl is perfectly round--a highly unusual event--you should definitely have it checked out before you buy it, as perfectly round cultured pearls are extraordinarily rare.

Step 4

Measure the diameter. The larger the pearl, generally the more valuable it is. Seed pearls tend to be 1 millimeter or less, while South Sea pearls can grow as large as 20 millimeters. It is very hard to get an oyster to grow a pearl over about 5 millimeters, so once the pearls exceed that size their value increases exponentially.

Step 5

These pink pearls all have the same basic color, size and shape, which makes the set more valuable

Rate the uniformity. If you are buying a set of pearls, then it is very important that they match in size, shape and color. Pearl harvesters have to sift through approximately 10,000 pearls to create a matching strand of beads, so the closer that the pearls are in appearance, the higher the quality of the jewelry. Remember, however, that this is another area that can either indicate high value or a total fake, as factory-poured pearls are easy to replicate in large numbers.