* Igneous rocks form from the cooling and solidification of molten rock (magma or lava).

* Metamorphic rocks form when existing rocks (igneous, sedimentary, or even other metamorphic rocks) are transformed by heat and pressure, without melting completely.

To transition from metamorphic to igneous, the following needs to happen:

1. Melting: The metamorphic rock needs to be subjected to temperatures high enough to melt it completely. This usually happens deep within the Earth's crust or mantle.

2. Cooling and Solidification: The molten rock (now magma) then needs to cool and solidify, forming new crystals and creating an igneous rock.

The Rock Cycle:

The process of metamorphic to igneous is a part of the rock cycle, where rocks are constantly being transformed through various geological processes:

* Igneous rocks can weather and erode into sediment, forming sedimentary rocks.

* Sedimentary rocks can be buried deep within the Earth, subjected to heat and pressure, and transform into metamorphic rocks.

* Metamorphic rocks, if subjected to even higher temperatures, can melt and become igneous rocks again.

So, instead of directly becoming igneous, metamorphic rocks can be a source material for the formation of new igneous rocks through the process of melting and subsequent cooling.