Although sedimentary rocks make up only a very small percentage of the Earth, they are the rocks that we see most. While igneous and metamorphic rocks usually form underground, sedimentary rocks almost always form on the Earth's surface, so more than 75% of the exposed rocks on Earth are sedimentary rocks.
Sedimentary rocks are further divided into three major groups:
- Clastic rocks: Rocks made from pieces of other rocks.
- Sorting Sediments: How clastic rocks form.
- Bioclastics: Rocks With No Minerals
- Evaporites: Rocks You Eat.