Spherical Pearls are the round, more traditional and most desirable shape. The more perfect and round the shape of the pearl, the more valuable it is.

Symmetrical Pearls are in pear shapes and other shapes that have symmetry from one side to another. These are not the true round shape. 

Baroque Pearls are the irregular shaped pearls. They generally are the less expensive category of pearls, but have a unique beauty that many prefer.