How does Chapter 19 use the analogy of a crystal to describe the nature of the Soul?

Chapter 19 provides a beautiful analogy to explain the pure and untainted nature of the Soul. It compares the Soul to a crystal, which, while appearing to take on the color of whatever is placed near it—be it red, black, or yellow—remains intrinsically pure, colorless, and distinct from those colors. In the same way, the Soul, though it appears in the world according to the actions of Maya and seems connected to the body and its experiences, remains fundamentally changeless and untainted. As Chapter 19 clarifies, the Soul is self-luminous, pure consciousness, and formless, merely appearing to be affected by its surroundings, much like the crystal.