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) day, Kino goes to sell his pearl. Unknown to him, the pearl dealers in La Paz are in cahoots with each other, secretly conspiring to make it appear as though the prices offered are competitive when they are defrauding the natives. They offer Kino a thousand pesos for the pearl when Kino believes that it is worth fifty thousand. Kino refuses to sell to the pearl dealers and decides to go to the capital instead. That night, Kino is attacked by more thieves, and Juana once again reminds him that the pearl is evil. However, Kino vows that he will