This chapter discusses the rock cycle and each of the three major types of rocks that form on Earth. Separate sections cover igneous, sedimentary, and metamorphic rocks individually.
TYPE OF ROCKS
...Sedimentary rocks form when sediments are compacted and cemented together (Figure below). These sediments may be gravel, sand, silt or clay. Sedimentary rocks often have pieces of other rocks in them. Some sedimentary rocks form the solid minerals left behind after a liquid evaporates.
This sandstone is an example of a sedimentary rock. It formed when many small pieces of sand were cemented together to form a rock.