* Both are formed from pre-existing rock: Igneous rocks form from the cooling and solidification of magma or lava, while metamorphic rocks form from the transformation of existing igneous, sedimentary, or even other metamorphic rocks due to heat and pressure.
* They can both be found in a variety of environments: Igneous rocks are found everywhere from volcanoes to deep underground, while metamorphic rocks can be found in areas of mountain building, along plate boundaries, or even in the Earth's crust.
* They can both be classified by their mineral composition and texture: Both types of rocks can be categorized based on the minerals they contain and the arrangement of those minerals. For example, both igneous and metamorphic rocks can be described as having a coarse or fine grain size.
* They both contribute to the rock cycle: Both igneous and metamorphic rocks are part of the continuous process of rock formation, transformation, and destruction known as the rock cycle.
Ultimately, while they differ in their formation processes, igneous and metamorphic rocks share a common origin and play important roles in the Earth's geology.
