In general the round pearl is the most valuable pearl shape. This is partly because a well formed round shape is relatively hard to find. Also most people recognize a round chocker of pearls.
A symmetrical pearl also should have well proportion symmetry. The outline should not have irregularities.
Baroque Pearls can have all different shapes; they can be shaped like a cone or a wing. Many times they are formed in the muscle tissue of the mollusk rather than its softer organs. If a pearl looks like it could be round but has an irregular deposit of extra nacre it is classified as a semi-baroque pearl. If all is equal in the valuing a baroque pearl will rank third behind spherical and symmetrical pearls.