Igneous Igneous rocks are formed by volcanoes. When the lava cools, it forms rock. A common igneous rock is obsidian. Obsidian is formed from a lava called rhyolite lava. Rhyolite lava is a thick form of lava that has lots of silica inside of it, which causes it to be less heavy than other lava. …
Continue reading “Igneous, Metamorphic, and Sedimentary Rocks”
Tyler's Geology 