Question: what is the difference between intrusive/plutonic and extrusive/volcanic igneous rocks?
Answer: Volcanic rocks are rocks formed when lava cools and solidifies on the earth's surface. Volcanic rocks are also known as 'extrusive igneous rocks' because they form from the 'extrusion,' or eruption, of lava from a volcano. ... Plutonic rocks are rocks formed when magma cools and solidifies below the earth's surface.