Volcanic rocks are classified as igneous rocks, and as their name suggests, form as a result of volcanic eruptions. Each rock is named based on the silica content of the magma being erupted, which ranges from felsic to ultramafic. Volcanic rocks are extrusive igneous rocks, and therefore are classified separately from intrusive igneous rocks.
Andesite is intermediate in composition.
Komatiite is ultramafic in composition, and is rarely seen on the Earth today except in flows that date back to the Archean.