Magma refers to the molten rock within the earth's crust. The molten rock that exits the vent of a volcano is referred to as lava. Pillow lava is lava that has erupted and flows beneath a body of water. The lava quickly solidifies and forms long pillow shaped chains. Pahoepahoe lava is smooth, viscous lava with a ropy and billowy surface.
AA lava is rough, jagged lava that has a spiny surface.
This lava could tear through about anything that crosses in its path. The majority of all volcanoes are made up of distinct types of igneous rocks. Intrusive igneous rocks are coarse grained and have cooled slowly within the earth's crust. Extrusive igneous rocks are fine grained and have cooled quickly outside of the earth's crust. Extrusive igneous rocks are often times referred to as volcanic rock.