Please explain the analogy of the gem and the stone that Baba uses to describe a disciple's development.

In Chapter 19, Baba uses an insightful analogy to compare different disciples' progress. He says that both a gem and a stone are rubbed on a whetstone—representing the Guru's guidance. While the process is the same for both, the outcome differs based on their inherent nature. A gem becomes a 'brilliant jewel' or a 'sparkling diamond,' its inner luster revealed. A stone, however, only becomes smooth and 'remains a stone.' This metaphor suggests that while a Guru provides the same teachings to all, a disciple's inner potential, faith, and readiness for transformation determine whether they will achieve true brilliance or only a superficial polish.