Pearls are made from parasites, not grains of sand

People like to point out that "a beautiful pearl is created from an irritating grain of sand," like "quit complaining, because irritating things are good in the long run." Problem being, it's not true. (How could it be true? Oysters would be full of pearls if this were the case. They literally live inside the sand. They're full of sand.)

In fact, natural pearls are created when a parasite enters the oyster. In order to protect itself, the oyster walls off the parasite with a pearl sac as a defense mechanism. In other words, every natural pearl basically has a tiny dead parasite in the center.

Image courtesy Flickr/cheesy42