what has changed about: The way Juana refers to the pearl? Juana and Kinos relationship?

She thinks the pearl is "evil". Juana and Kino become more separated emotionally. Kino is obsessed with the pearl.

Kino became abusive when Juana tried to throw the pearl back into the sea. She believed it to be evil, and once she saw that Kino killed a man she felt that throwing it away was useless.

At one point Juana attempts to rid her family of the evil by throwing it in the ocean. Kino stops her and strikes her.