With the wide variety of shapes available in black Tahitian Pearls, understanding how shape affects value is important. Of course, the roundest pearls—those perfect spheres—are the most valuable pearls whereas ringed pearls are least valuable when compared. However, the shape of a pearl does not affect its beauty, it simply affects its price. This is because round Tahitian pearls represent a small percentage of the pearls harvested in the world. Therefore, it is the roundest Tahitian pearls that are the rarest which have the best chance of appreciating over time.

Round (most valuable) pearls are almost perfect spheres whose diameter variation rate is less than 2%.

Semi Round (2nd most valuable) pearls are slightly imperfect spheres whose diameter variation rate is greater than 2% but less than 5%.

Semi Baroque pearls include button, drop, pear and oval. These pearls exhibit at least one axis of symmetry and are mostly used in irregular shaped necklaces and jewelry pieces such as pins, pendants and rings because of their imperfect shapes.

Baroque (2nd least valuable) pearls do not have an axis of symmetry.

Circle or Ringed (least valuable) pearls are characterized by regular streaks or rings, perpendicular to an axis of symmetry, over more than one third of the pearl's surface.