Types of rocks
By Gabrielle Crkvencic
Did you know that igneous rock can form when a volcano erupts, or underwater, or underground?? We'll they do, rocks like obsidian form deep in the earth or in a volcano because it's smooth, rocks like pumice form underwater because it has many bubbles.
1. Sedimentary rock
3. Metamorphic rock
Marble and quartzite are some examples of metamorphic rock. The word metamorphic came from the Greek word "to change form". The reason we call it metamorphic rock is because under heat and pressure it can change how it looks.