Can you explain how Chapter 19 uses the metaphors of a crystal and a rope to describe the true nature of the Soul and the illusion of ego?

Chapter 19 explains that the Soul, while appearing in the world due to Maya, remains pure and untainted. It uses the metaphor of a crystal, which may appear red, black, or yellow depending on the color placed near it, yet it remains intrinsically distinct, pure, and colorless. This illustrates how the Soul is unaffected by worldly attributes. The text further clarifies the illusion of ego by comparing it to mistaking a coiled rope for a snake. Just as the snake is a false superimposition on the rope, the ego of 'I am the body' is a false bondage for the liberated Soul, which is truly distinct from the body, senses, and mind.