Irritate an oyster, you might get a pearl

Meat isn’t the only thing found inside an oyster shell. Sometimes, there’s a pearl.

While humans value pearls as jewelry, for an oyster, they are a way to protect itself from an irritant that slips inside the shell as it opens and closes to get nutrients in the water.

As an oyster grows in its shell, it pulls minerals out of the water and has an organ that creates the coating on the inside of the shell. If an irritant like a small parasite slips between the inside of the shell and that organ, the oyster coats it with the same substance that it uses to create the inside of the shell.

Over time, the irritant gets covered in layer after layer of that substance and the pearl grows. The longer the irritant has been inside the shell, and the older the oyster gets, the bigger the pearl.

The pearls used in jewelry are round, but others wind up in odd shapes.

Some pearls form naturally, but others, known as cultured pearls, are created by inserting a special irritant inside the shell. Some oysters are grown specifically for producing pearls, which can be removed without killing the oyster, and new irritants inserted to grow more.

Northwest oysters aren’t grown for their pearls, but you might find one from time to time when eating raw oysters. Shuckers on the production line also sometimes find them as they open oysters for processing, although they aren’t usually perfectly round or very big.

Taylor Shellfish Farms lets shuckers take home any pearls they come across, said Bill Dewey, the company’s senior director of public affairs. It has its own beds for cultured pearls elsewhere.