Learn the definitions to all those jewelry terms you don't know.
A pearl that forms naturally when a grain of sand or other small irritant enters the pearl. If the oyster is unable to eject the object, the oyster will coat the object with layers of nacre to form a pearl. Natural pearls are very rare. There is no way to determine if an oyster contains a pearl, so to create a dependable pearl supply, the culturing process was invented.