Pearling is the process of cultivating pearls from oysters or other mollusks. It involves inserting a small bead or piece of tissue into the mollusk, which then secretes layers of nacre around the irritant, eventually forming a pearl. This practice is primarily associated with oysters, but can also involve clams and mussels. The cultivation of pearls can take several years, depending on the type and size of the pearl desired. There are different types of pearls, including natural pearls, which form without human intervention, and cultured pearls, which are created through the pearling process.