Volcanic rocks are formed from the solidification of molten lava that erupts from a volcano. When lava cools quickly, it creates fine-grained rocks like basalt, while slower cooling can produce coarser rocks like granite. These rocks are typically found near volcanic regions and can vary in color and texture. There are two main types of volcanic rocks: extrusive and intrusive. Extrusive rocks form on the Earth's surface after a volcanic eruption, while intrusive rocks form beneath the surface. Common examples of volcanic rocks include pumice, which is light and porous, and obsidian, which is glassy and dark.