Here's why:
* Formation: Igneous rocks form from the cooling and solidification of magma (molten rock below the surface) or lava (molten rock that has erupted onto the surface).
* Abundant Source: Magma and lava are incredibly abundant within the Earth, constantly being generated by tectonic processes.
* Erosion and Weathering: While sedimentary rocks are also prevalent, they form from the breakdown and re-deposition of other rock types. Since igneous rocks are the source of these sediments, they are ultimately the most abundant.
Note: While igneous rocks are the most common by volume, sedimentary rocks are the most common type of rock you would likely encounter on the surface. This is because they cover large areas of the Earth's landmass and are often exposed due to erosion.
