It is human invention to control the shape and size of the pearl. As cultured pearl, the shape of pearl can be controlled through the nucleus. The pearl oyster is implanted with the desirable size or shape of nucleus to stimulate the release of nacre layers to cover over nucleus’s surface. Then, the grafted mantle tissue is inserted into the tissue of the pearl oyster at its position and the cultured pearl will be formed and ready to cultivate after 1 to 2 years.
The Mabe pearl, Akoya pearl, South Sea pearl and Rather Round pearl are categorized as the cultured pearl.
The process of forming natural and cultured pearl are the same, the only difference is the way on how the oyster receive the foreign object before forming the beautiful pearl.