What type of rock is shown?

These are igneous rocks. You may have chosen sedimentary rock based on the visible layering. Most of the time, layering is a good clue to sedimentary origins. However, volcanic materials such as lava and ash can also accumulate in layers. In this case, the photo shows the inner crater wall of the volcano Poás in Costa Rica.

To learn more about Costa Rican volcanoes firsthand, visit with Scripps scientist Dr. David Hilton, at Volcano Expedition.