Pearls are made by marine oysters and freshwater mussels as a natural defence against an irritant such as a parasite entering their shell or damage to their fragile body. The oyster or mussel slowly ...

Natural pearls form when some kind of irritant, usually a small organism, makes its way into the shell of a mollusk like an oyster or a mussel. To protect itself from the invader, the mollusk ...

A retractable foot, a siphon for sucking up water, powerful muscles, and, sometimes, a pearl ... Old shell. Benji: Oh, I got a crab. Narrator: Then we stumbled upon what's known as a honey ...

Thinning may solve the problem, Müller says, because lower shell density usually results in a higher quality pearl. "In effect, the farmers will be getting more with less," he says. Others feel ...

Pearls are the result of a mollusc's reaction to irritants such as parasites that enter its shell. Although model pearls are perfectly round and smooth, in reality they come in a huge number of shapes ...