Geology Rocks: Metamorphic Rocks

Contributor: Meghan Vestal. Lesson ID: 11101

How is a butterfly like the statue of David? They both have gone through metamorphosis! Rocks can change form to become different rocks. Transform yourself into a rock expert with this fun experiment!


Earth Science

learning style
Kinesthetic, Visual
personality style
Lion, Beaver
Grade Level
Middle School (6-8)
Lesson Type
Dig Deeper

Lesson Plan - Get It!


Michelangelo’s statue of David is one of the most famous statues in the world. This statue is made of metamorphic rock, but at one time the stone was considered sedimentary. How did this sedimentary rock change into a metamorphic rock? Let’s find out!

Before you begin digging into this lesson, review the formation of igneous and sedimentary rocks discussed in the previous Related Lessons, found in the right-hand sidebar.

Write a paragraph explaining how each type of rock is formed. Have your teacher or parent check your writing.

In this lesson, you will learn about the third and final type of rock: metamorphic rocks.

In order to gain a deeper understanding of how metamorphic rocks are formed, look up the definition for the term ‘"metamorphosis." If you do not have a dictionary available, use Merriam-Webster’s Online Dictionary. After you have looked up the definition, think about how this definition could relate to metamorphic rocks. Discuss your ideas with a teacher or parent.

The name "metamorphic rock" comes from the term "metamorphosis," because the formation of a metamorphic rock involves changing the structure of an igneous or sedimentary rock.

In order for a metamorphic rock to form, an igneous or sedimentary rock must be exposed to extreme heat or pressure. Examples of situations that could create metamorphic rocks include heat from within the Earth, pressure created by the movement of the Earth’s plates, and pressure created as layers of Earth push down on the different types of rocks that already exist in the Earth.

It is important to keep in mind that when heat is involved in the process of forming a metamorphic rock, it does not fully melt the rock. Rather, it transforms it into a more dense rock. Metamorphic rocks are always formed within the Earth.

Like sedimentary rocks, metamorphic rocks often have layers, although the layers in a metamorphic rock appear slightly different. Layers in a metamorphic rock are often more curved or bent. Sometimes, the layers are a different density.

Metamorphic rocks are always formed from igneous or sedimentary rocks. Use the flow charts to see what metamorphic rocks were formed from:

Limestone (sedimentary) Marble
Granite (igneous) Gneiss
Sandstone (sedimentary) Quartzite
Basalt (igneous) Granulite
Mudstone (sedimentary) Slate


To continue learning about sedimentary rocks, watch the StudyJams! Metamorphic Rocks slideshow. When you visit the StudyJams! site, just click the green Slide Show button. You will Test Yourself later in the lesson.

Look at the question from the beginning of the lesson. Michelangelo’s statue is made of marble. How is it that this marble statue, which is classified as a metamorphic rock, was once sedimentary rock? Explain your answer to a teacher or parent.

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