How does Chapter 19 use the analogy of a crystal to explain the true nature of the Soul and its interaction with Maya?

Chapter 19 employs the analogy of a crystal to explain a profound philosophical concept about the Soul. The text states that the Soul, while inherently changeless and pure, appears in this world according to the actions of Maya (the Unmanifest Nature). It is compared to a clear crystal that remains pure and distinct from all colors, yet appears to take on the color of an object placed near it, whether red, black, or yellow. In the same way, the Soul remains untainted and self-luminous, even as it appears to be associated with the body, senses, and mind. This illusion is further compared to seeing a snake in a rope; the ego of 'I am the body' is a false superimposition on the true, formless nature of the Soul.