A guide to the different types of pearls and where they come from: Natural versus cultured pearls: The life of the natural pearl begins when a foreign object such as a parasite or piece of shell ...

Oysters are the main producers of pearls, but clams and mussels can also create them. Pearls form when oysters secrete layers of nacre around irritants. There are natural and cultured pearls, with ...

• Natural pearls: Formed without human interference, these are incredibly rare. • Cultured pearls: The process is natural, but guided by farmers who carefully place a nucleus inside the mollusc to ...

Among the world's 8,000 species of mollusk, only about 20 produce pearls. Found in rivers and seas from Scotland to French Polynesia, these shell fish yield gems in more flavors than you'll find in a ...

Everybody knows how oysters make pearls — a bit of sand or grit slips through the protective barrier of their outer shell, irritating the mollusk’s body, and the invertebrate encircles the invader ...