Question: igneous rock that forms when lava cools on earth's surface?
Answer: An is one that forms when lava cools on Earth's surface. Granite is a common intrusive rock in continents. If magma with the same composition reaches the surface, it forms extrusive rocks such as rhyolite and pumice (PUHM-ihs). Basalt (buh-SAWLT) is an extrusive igneous rock that forms the ocean floor.