What is fascinating about this story is the way that the novel charts the transformation in Kino himself after finding the pearl, which should ideally make him happy and an easier person to be around. However, in this dog-eat-dog world that Steinbeck presents us with, the finding of great wealth becomes a source of deep sadness and mourning, which is something that Juana becomes aware of as she calls the pearl "evil." Note how it turns Kino paranoid after the initial reaction that he receives from both the villagers and others, such as the doctor. When Juana asks him who he fears, Kino's response is particularly telling:
Kino searched for a true answer, and at last he said, "Everyone." And he could feel a shell of hardness drawing over him.
This "shell of hardness" is something we increasingly see in the character of Kino as he even turns against Juana in his attempt to get the correct amount of money for the pearl that he has found and comes to curse his life so profoundly.