Metamorphic rocks are formed when heat or pressure is applied to Sedimentary or Igneous rocks. The Metamorphic rock is determined by the parent rock. Some examples are:

 

Parent Rock	>>>>>>>>>>>>>>>>>>>>>>	Metamorphic Rock
Sandstone	>>>>>>>>>>>>>>>>>>>>>>	Quartzite
Shales and Mud	>>>>>>>>>>>>>>>>>>>>>>	Slate

There are two main groups of metamorphic rocks. These are determined if they changed by heat or pressure. These two main groups are:

Regional Metamorphic rocks > created mainly by pressure

Contact Metamorphic rocks > created mainly by heat