Natural and cultured pearls both come from the same sources and are not artificially created. Natural pearls are the result of no intention or assistance by humans, but only the phenomenon of the mollusk's normal processes. Cultured pearls come from mollusks that are bred and tended to by farmers in order to create pearls for harvest. The cultured pearls are created by inserting a small bead or tissue into the mollusk, which then coats the object with layers of nacre to form a pearl.
Cultured Pearl Education Guide | Jared