Rock Identification & the Rock Cycle

There are three main types of rock: sedimentary, metamorphic, and igneous. They are named by how they are formed.

Sedimentary rock forms from sediment – small particles of materials, such as bits of sand, rock and shell. The sediment settles into layers and over a very long period of time eventually hardens into rock making it ideal for forming fossils. Sedimentary rock can maintain its particle-like materials and be easy to break up and crumble. Looking for these materials (sand, rock and shell) is one way to quickly identify sedimentary rock. Examples of sedimentary rock are limestone, sandstone and conglomerate.

Metamorphic rock forms under great pressure. This metamorphosis, or change, happens deep under the surface of the Earth where there is extreme heat and pressure. Metamorphic rocks often run in long ribbon-like layers with growths of crystals on their surface. Examples of metamorphic rocks are marble and gneiss.

Igneous rock forms when the molten rock deep within the earth, called magma, cools and hardens. This can happen on the Earth’s surface when the magma erupts from volcanoes as lava and cools in the air or water (in underwater eruptions) or under the Earth. Because the magma cools quickly, it hardens with no crystals leaving the resulting rock shiny and sometimes glass-like or full of holes where air gas bubbles may have been trapped. Examples of igneous rock are obsidian and basalt.

Print out the color and black and white models, the study text and an assessment quiz using the PDF link below.

Students can create their own model with: Rock Formation Coloring.

Rock Quiz - How Do The Three Rock Types Form?

Sedimentary rocks form: ________________________________________________________________________________________________________________________________________

Metamorphic rocks form: ________________________________________________________________________________________________________________________________________

Igneous rocks form: ________________________________________________________________________________________________________________________________________

List 6 characteristics you can use to help identify rocks:

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2. __________________________________________________________________________________________________________________________________________________________

3.  __________________________________________________________________________________________________________________________________________________________

4. __________________________________________________________________________________________________________________________________________________________

5. __________________________________________________________________________________________________________________________________________________________

6. __________________________________________________________________________________________________________________________________________________________

Print this quiz fron the PDF below.