Volcanic rock is a type of igneous rock that forms from the solidification of magma or lava. It is created when molten rock erupts from a volcano and cools down before it reaches the surface. The composition of volcanic rocks can vary greatly depending on the specific types of magma or lava that was erupted, as well as the conditions under which they solidified. Some common examples of volcanic rocks include basalt, andesite, rhyolite, and tuff. These rocks are often characterized by their crystal-poor composition and can be identified by their distinctive mineralogy and textures.