Metamorphic rock used to be igneous or sedimentary rock that was changed by heat or pressure or both. The Appalachian Mountains including the Blue Ridge are mainly metamorphic rock with a little igneous rock.
Make about 2 dozen pea-sized balls from clay of different colors to represent rock particles.
Place the clay balls close together on a piece of waxed pager. Place a second sheet of
waxed paper on top of the clay balls.
Now, put stack some books on top of the waxed paper. Imagine that the books are layers of rock building up on top of the rock particles. The pressure of the rock particles increases as you add each book. Heat builds as the rock particles are pushed deeper into the Earth's crust.
Now remove the books and peel away the waxed paper. Look at the clay. An entirely new kind of rock has been formed. The same thing happens to igneous and sedimentary rocks when they are changed.
The source of this article taken from Wherever You Are On Earth. . .You're On Rock! by WHAM, the mineral information company. If you would like additional educational information and materials, stop by at www.aggman.com