Traditional Saltwater Pearls
Traditionally, most pearls were gathered from saltwater-dwelling mollusks in the Persian Gulf, the Red Sea and the coastal waters of India and Japan. These saltwater pearls were referred to as marine pearls. Natural saltwater pearls are still found, but the yield is too small to account for any significant market share.
Shape of Saltwater Cultured Pearls
Saltwater cultured pearls tend to be more round than freshwater cultured pearls. This is due to the fact that saltwater mollusks are universally bead nucleated. Unless the saltwater pearl is a keshi pearl, it will have a bead core.
Saltwater pearls are cultured by prying open the mollusk 2-3 centimeters. A technician then uses a special instrument to make a minute incision on the gonad (reproductive organ) of the animal. A small bead nucleus is inserted into this hole, and a tiny piece of mantle tissue is then placed behind it. The epithelial cells in this mantle tissue grow around the nucleus producing a pearl sac. This is where the pearl grows. This process is the same for all saltwater pearls cultured today.