Answer:Dark minerals rich in iron and magnesium separate from light minerals rich in silica and aluminum.
Explanation: Metamorphic rocks are rocks formed as a result of the transformation of other existing rocks which can be Igneous or Sedimentary rocks,this transformation process is called METAMORPHISM. During metamorphism,rocks under Serious levels of stress which can lead to the separation of materials.
During this separation process,Dark minerals rich in iron and magnesium are separated from light minerals rich in silica and aluminum.