In the day of the rule of Natural Pearls, truly 100% round shaped pearls were once very difficult to obtain, thus they commanded a much higher prize. Because of this scarcity of round pearls, the most valuable shape was that of a tear-drop (the name "pearl" is tought to originate from the Spanish-Italian word "pera": pear), but button-shaped pearls were used to provide the illusion of a round pearl (when properly set these pearls look round).

Later on, with the appereance of the cultured pearl, the perfectly spherical shaped pearl became much more common. It was said that only from 5 to 25% of a pearl harvest came out round to semi-round in shape, but nowadays that number has increased to over 90% (due to a decreasing of the nacre thickness). Due to the ancient shape and value considerations (originated with natural pearls), a round shape takes first place in value, followed by "off-round" (about 2-5% of the pearl's shape is not-round), semi-baroque (symmetrical shapes: drops, buttons, ovals) and finally baroque shapes (asymmetrical pearls). Depending on the source, circled pearls may be considered in their own group (circlé) or as part of the semi-baroque group. Circled pearls may have one or more "belts" or constrictions that will give the pearl a very unique appereance.

Semi baroque pearls are highly coveted in some countries, especially in the drop shapes, where they are known as "cabochons", "tears" or "pears". They are very popular in drop-style jewelry and used mainly in pendants and earrings. Baroque pearls do not have a definitive shape, being always irregular in their skin/surface, coloring and appearance. Sometimes, keshi pearls are easily mistaken with baroques, the main difference being the presence of a nucleus in the latter. Baroque pearls are very unique, so they can give a more natural look to jewelry.

Desde la introducción de la Perla de Cultivo Japonesa en los albores del Siglo XX, las personas comenzaron a creer que la forma "natural" o "tipíca" de las perlas es la de esféra o redonda. Pero esto no siempre fue así: hasta antes de ese acontecimeinto, la forma normal de la perla era inesperada: podía ser de gota, barril, botón, alargada, ovalada, totalmente caprichosa o incluso...esférica.

A partir del momento en que el hombre comienza a producir la perla de cultivo, estas comienzan a tener formas más regulares con gran tendencia a la esférica. Y cuando la calidad de las perlas comenzó a disminuir (con períodos más cortos de cultivo) también aumentó la proporción de perlas redondas.

Las Perlas del Mar de Cortez se asemejan más a las antiguas perlas naturales, ya que poseen formas muy variadas y apenas un 2% de la cosecha alcanza a tener forma esférica. En este sentido es importante que el cliente tenga en mente que su perla siempre va a ser ÚNICA: su forma, su color, su lustre, etc., va a ser diferente a otras perlas.

La forma de la perla también es un fuerte indicador de su precio. La forma considerada como la más valiosa es la redonda, seguida por la forma “semi-redonda” (off-round), luego siguen las formas simétricas (semi-barrocas) en el siguiente orden: la de gota o “calabacín” (cabouchon), los óvalos, la de botón (button). Las formas más económicas –por su abundancia- son las barrocas (asimétricas) y por último las perlas “anilladas” (circlè).