Pearls

Evaluating Pearls
The quality and price of a particular pearl is determined by its size, luster, shape, color, and blemishes. It is also important to take the nacre, or skin of the pearl, into consideration when you are evaluating the quality of such a jewel. Of course, if a pearl is left in an oyster for a long period of time, it will develop a thicker pearl skin. This thicker nacre is desirable because pearls with this trait do not lose their luster as readily as pearls with a thin nacre.

Size
The larger pearls are more expensive than the smaller pearls, as these smaller pearls are much more common. This situation occurs because it is difficult for an oyster to grow a pearl larger than five millimeters. However, the most popular size of pearls sold around the globe is approximately seven millimeters. It is important to keep in mind that the size of the oyster directly affects the size of the pearl it creates. Smaller mollusks, for example, create smaller pearls with fewer surface defects. However, large cultured pearls also require a larger nucleus to be implanted into the oyster. The larger nucleus does increase the chance of the mollusk rejecting the nucleus, or dying though.

Additionally, different shaped pearls are measured differently. Round pearls, for instance, are measured according to their diameter in millimeters, while their length and width in millimeters measure baroque pearls.

Surface
Since oysters in nature grow cultured pearls, it is rare to find a pearl whose surface is free from imperfections. These include pits, spots, bumps, circles, wrinkles, and cracks on the surface. As you may think, fewer surface imperfections make a pearl more valuable. On the other hand, a high degree of luster can also make the imperfections less visible.