Deep below Earth's surface, rocks can undergo great change. They are heated by the high temperatures at great depths.
They are under pressure from the rocks lying above. Great heat and pressure can change on rock into another rock. A rock formed under heat and pressure from another kind of rock is called Metamorphic Rock. In the process, the original rock does not melt under heat and pressure. If it did, it will become an Igneous Rock. Instead, the original rock remains solid.
- Limestone ----> Marble
- Granite ----> Gniess
- Shale ----> Slate ----> Schist
- Sandstone -----> Quartzite