Igneous Rock

geology · earth science · rocks · molten

Born from lava. Igneous rocks form when hot, melted rock called magma rises from deep underground and cools down. If the magma erupts from a volcano, it's called lava, and when it cools quickly on the surface, it creates igneous rock.

Fast or slow cooling. How quickly the magma cools affects what the rock looks like. Fast cooling makes tiny crystals you can barely see, while slow cooling deep underground makes bigger crystals you can spot with your eyes.

One of three types. Igneous rocks are one of the three main types of rocks on Earth. The other two are sedimentary rocks (made from compressed sand and shells) and metamorphic rocks (made when rocks get heated and squeezed deep underground).

Crystals tell the story. You can often see shiny crystals sparkling inside igneous rocks. These crystals formed as the magma cooled, and their size and type tell scientists how and where the rock was created.

Super common everywhere. Igneous rocks make up a huge part of Earth's crust and are found on every continent. Basalt and granite are two of the most famous igneous rocks you might see.