Kino's first mistake is announcing that he has discovered the Pearl of the World. Word of Kino's discovery quickly spreads throughout the village and town as jealous individuals begin plotting his demise.

Kino makes another significant mistake by hiding the pearl in his home. By hiding the pearl in his home, Kino puts his entire family in danger as ruthless thieves attempt to steal the pearl.

In addition to hiding the pearl in his home, Kino also allows the doctor to administer medicine to Coyotito, even though his son seems to be making a recovery. Juana's homemade remedy seems to be working, but Kino allows the doctor to give Coyotito medicine, which has an adverse reaction.

Kino also naively believes that the pearl dealers will give him a fair deal. He ends up discovering that they are all determined to undermine and cheat him.

Kino's greatest mistake is dismissing Juana's suggestion to get rid of the pearl. Juana is an insightful woman who realizes that the pearl has completely consumed Kino and is destroying their family. When she attempts to throw the pearl into the ocean, Kino strikes her and prevents Juana from getting rid of the pearl.

After Kino kills a man in self-defense, he is forced to flee his village and puts his family in danger as trackers search for him throughout the wilderness.