Pearls form when oysters coat irritants with nacre over years. Learn how natural and cultured pearls are created and why oysters matter.

For centuries, researchers have puzzled over how oysters grow stunningly symmetrical, perfectly round pearls around irregularly shaped grains of sand or bits of debris. Now a team has shown that ...

A pearl does not begin as something precious. It begins as a problem. Inside an oyster, a tiny particle slips in and settles where it does not belong. It might be a parasite, a rough fragment, or ...