Shape in pearls is divided into three categories: spherical, symmetrical, and baroque. The rarest and most valuable is the spherical or round pearl.; these are judged on their degree of "sphericity" or roundness. While fine pearls that are perfectly round are extremely rare, the closer a pearl comes to being perfectly round, the more expensive it will be.

Pearls with shapes such as teardrop or pear-shape are symmetrical pearls, and are judged on proportioning, outline, and good symmetry; that is, whether they have a nice, pleasing, well-balanced shape. Any strand of pearls should be well matched for shape, and when worn give the appearance of uniformity. Terms such as semi-round and semi-baroque are also used.

These are terms applied to pearls that are "out of round" but not so much that are irregular shape is interesting, or distinctive. These cost much less than other shapes. Symmetrical pearls are less expensive than round pearls-although there are some exceptions-but much more expensive than baroque pearls, which are irregularly shaped pearls.