Why did Dove give Johnny a cracked crucibal?

Dove gave Johnny a cracked crucible as a cruel prank, intending to undermine his confidence and show his superiority over Johnny. This act symbolizes Dove's jealousy and desire to assert dominance, reflecting the competitive nature and harsh realities of the apprentice system in the story. The cracked crucible also serves as a turning point for Johnny, prompting him to prove his worth and resilience despite the challenges he faces.