|The rocks in the forground are Navajo Sandstone created from great shifting sand dunes during the Jurassic Period, 150 million years ago.|
Rocks are all around us. They make up the backbones of hills and mountains and the foundations of plains and valleys. Beneath the soil you walk on and the deep layers of soft mud that cover the ocean basins is a basement of hard rock.
We can learn something about the way a rock formed from by looking carefully at the evidence preserved inside. What a rock is made of, the shapes of the grains or crystals within the rock, and how the grains or crystals fit together all provide valuable clues to help us unlock the rock's history hidden within.
Sedimentary rock can be deeply buried, subjected to heat and pressure, which over time, cause it to change its structure into a new rock, a metamorphic rock. Metamorphism is a big word meaning change. Eventually, these metamorphic rocks may be heated to the point where they again melt into magma.
Note that the rock cycle doesn't always have to work in this order; sometimes igneous rocks can be buried and metamorphosed, skipping the sedimentary rock phase, and sometimes sedimentary and metamorphic rocks can be uplifted and eroded to form new sedimentary rocks. It is also possible for rocks to remain unchanged in stable regions for long periods of time.