Kino thinks that the pearl is the answer to all his prayers. Now that he's in possession of this valuable object, he's certain that all he has to do is sell it for a huge sum of money, and he and his family will be set for life. Unfortunately, that's not how things turn out. The pearl soon starts to cause more trouble than it's worth, and it brings great pain and emotional suffering to Kino's loved ones. It's only when Kino's son, Coyotito, is shot by a gang of thugs sent to steal the pearl that Kino realizes that this precious item just isn't worth it.
Kino's wife, Juana, never shared her husband's enthusiasm for the pearl. She sensed from the start that it would bring them nothing but misfortune. After some pearl brokers try to cheat Kino out of a fair price for his find, Juana immediately suggests that the pearl be destroyed. Later on, much to Kino's horror, she will try to throw it back into the sea.
The doctor sees the pearl as an opportunity to make a fast buck. As a member of the racial and social elite, he doesn't believe that the indigenous Kino is entitled to a fair price for the pearl. So, he cynically tries to cheat him out of it, going to extraordinary lengths to do so. For centuries, the doctor's people have gradually taken over this part of Mexico from the indigenous people. As far as they're concerned, everything of value in the country, whether on land or at sea, belongs to them. They will use whatever means necessary, even resorting to violence, in order to keep what they believe is rightfully theirs.