What type of rock is primarily formed from volcanic activity?

Igneous rock is primarily formed from volcanic activity because it crystallizes from molten rock material, known as magma or lava. When volcanic eruptions occur, magma rises to the Earth's surface and erupts as lava. As this lava cools, it solidifies into igneous rock. The texture and composition of igneous rocks can vary depending on how and where they cool. For example, if the lava cools quickly on the surface, it may form a glassy texture, whereas slow cooling beneath the surface leads to the formation of larger crystals.

In contrast, metamorphic rocks are created from existing rocks that undergo transformation through heat and pressure, rather than direct volcanic activity. Sedimentary rocks, on the other hand, are formed from the accumulation and compaction of sediments over time, generally in aqueous environments. Foliated rocks, while a sub-class of metamorphic rocks, exhibit a layered or banded appearance due to the alignment of mineral grains under pressure, and are also not formed from volcanic activity. These distinctions highlight why igneous rock is specifically associated with volcanic processes.