Cultured pearl is calcium carbonate and a fibrous protein called conchiolin. As the nacre builds up in layers of minute aragonite tablets, it fills the growing pearl sac and eventually forms a pearl. Natural pearls are formed by nature, more or less by chance. On the other hand, cultured pearls are human creations formed by inserting a tissue graft from a donor oyster, upon which a pearl sac forms, and the inner side precipitates calcium carbonate, in the form of nacre or "mother-of-pearl". The most popular and effective method for creating cultured pearls are made from the shells of freshwater river mussels
The Pearl (novel) develops throughout the novel. He begins as a hard-working, simple man that has a wife, Juana, and a son, Coyotito. He is content with his life-style as a diver but is not wealthy until he discovers the pearl. After discovering the pearl, Kino gradually changes to become a completely different man. Though his family is still the center of his actions, he is also driven by greed. Quickly, he becomes obsessed with the material things that the pearl could bring, which is drastically different than before. He is no longer content with his son being uneducated, or his family not