What is the most abundant type of rock in the Earth's crust?

Igneous rock is the most abundant type of rock in the Earth's crust due to its formation process, which is closely linked to the activity of magma and lava within the Earth. When magma cools and solidifies, it forms intrusive or plutonic igneous rocks, such as granite, which make up much of the continental crust.

Additionally, when lava erupts at the surface and cools rapidly, it forms extrusive or volcanic igneous rocks, like basalt. Basalt constitutes a significant part of the oceanic crust. Overall, the process of magma formation is prevalent throughout the planet's geological history, leading to a higher volume of igneous rock compared to metamorphic and sedimentary rocks, which typically require additional processes such as heat, pressure, and sediment compaction for their formation.

This abundance emphasizes the importance of igneous rocks in the structure of the Earth's crust and its overall geology.