What is the difference between a natural and a cultured pearl?
A natural pearl (often called an Oriental pearl) forms when an irritant, such as parasite, works its way into a particular species of oyster, mussel, or clam. As a defense mechanism, the mollusk secretes a fluid to coat the irritant. Layer upon layer of this coating is deposited on the irritant until a lustrous pearl is formed. With a cultured pearl, the difference is that the irritant is a surgically implanted bead or piece of shell called Mother of Pearl. Once the bead is implanted, the oyster begins secreting layers of nacre to form the pearl. The core of a cultured pearl is much larger than in a natural pearl.
