* The Rock Cycle: The transformation of rocks follows a cyclical process known as the rock cycle. Igneous rocks form from the cooling and solidification of magma or lava. Metamorphic rocks form when existing rocks (igneous, sedimentary, or even other metamorphic rocks) are subjected to intense heat and pressure.

* Melting is Key: For a metamorphic rock to become igneous, it must undergo melting. This melting can be caused by:

* Heat from magma intrusion: Magma rising from deep within the Earth can melt surrounding rocks.

* Buried deep within the Earth: The immense pressure and heat found deep within the Earth's crust can melt rocks.

The Process:

1. Melting: The metamorphic rock melts, transforming into magma.

2. Cooling and Solidification: The magma cools and solidifies, either underground (forming intrusive igneous rocks) or on the surface (forming extrusive igneous rocks).

In summary, the process is not a direct transformation but rather a cycle:

1. Metamorphic Rock → Melting → Magma → Cooling and Solidification → Igneous Rock

Important Note: The rock cycle is continuous. The igneous rock formed from a melted metamorphic rock can then be subjected to weathering, erosion, and deposition, leading to the formation of sedimentary rocks. These sedimentary rocks can later be metamorphosed, completing the cycle.