Sometimes new minerals are formed by chemical reactions when solid rocks meet magma. The rocks that are formed when these processes happen are called metamorphic rocks. Marble is a metamorphic rock that was once the sedimentary rock limestone. Quartzite is a metamorphic rock that used to be sandstone. Granite is an igneous rock that can change into gneiss from the heat and pressure inside the Earth.
Question
Can you find any other examples of metamorphic rocks?
Question
What do you notice about all metamorphic rocks?