A pearl is created by oyster, Clamps and Mussels, interestingly pearl is created by accident😵, yeah its true 😄
Oysters that creates pearl are quite simple creature, languished in water and lived on by plankton. well the oyster possibly feed a grain of sand or a parasite lodged itself inside the soft body of oyster causing the host a discomfort.
The oyster want to protect itself from the intruders so it started to creat a shield around the intruders, the shield is like smooth hard crystal substance, oysters creates that substance one layer upon another on other. This substance is calcium carbonate based refer to necker, as long as the intruder in on the shell the oyster will continue build necker shield around the that and in a few years the substance will totally under a cocoon of smooth and shining which we know as The Pearl...