Based on Chapter 19, what is the true nature of the Soul, and how does it appear in the world without being tainted?

According to Chapter 19, the Soul is self-luminous, pure consciousness, changeless, and formless. It is distinct from the body, senses, mind, and life-force. The chapter explains that the Soul appears in this world through the actions of Maya (the Unmanifest Nature). However, it remains untainted by its worldly association, much like a crystal that appears to take on the color of a nearby object but remains inherently pure and free from change. Chapter 19 uses this analogy to illustrate that while the Soul may seem affected by the world, its true nature is eternally pure and untainted.