The term "Luminous Mantle" refers to a specific layer of the Earth's interior, located between the crust and the outer core. This layer is composed of semi-solid rock that can flow slowly over geological time. The mantle plays a crucial role in the movement of tectonic plates, which are responsible for earthquakes and volcanic activity. The "luminous" aspect of the mantle is often associated with its ability to emit light due to the presence of certain minerals and the high temperatures within. This phenomenon can be observed in some geological formations, where minerals like fluorescent materials glow under specific conditions, providing insights into the Earth's composition and processes.