Do all Oysters have pearls in their shells? How does a pearl help the oyster? Does it? How does a pearl form? Here are the answers to those commonly asked questions.
It starts out when an oyster is just sitting there, sucking in food that is floating around in the ocean (you know, algae, little pieces of rotten meat, or whatever oysters eat), when in comes a piece of sand or debri and gets stuck inside the shell. Oysters are sanitary creatures, and they sure don’t want anything contaminating their food, so, they secrete calcium carbonate (same thing the shell is made of, and also known as nacre) over the debri, totally encasing it with the hard substance. Then, along comes a pearl diver, grabs the oyster and opens it up to get the pearl.
Nowadays, people culture oysters in oyster farms and put a grain of sand into the oyster’s shell, and come back a few years later to collect the pearls. Pearls that are not pefectly round are called baroque pearls, and are worth considerably less than pearls that are perfectly spherical. I bought a string of 70 baroque pearls for $3 at a gem show, and even though they are not valuable, they are beautiful, some having little points on them.
What many people do is put tiny statues inside instead of sand grains, and the nacre forms over the ridges and carvings, forming a pearl replica of the statue.