Earth Science - Middle School
Table Of Contents: Classifying Rocks
1. Rock Definition
Rocks are solid, naturally occurring substances composed of one or more minerals and other matter. Rocks are classified into three groups according to how they are formed.
2. Igneous Rocks
Igneous rocks form when liquid rock cools and hardens.
3. Sedimentary Rocks
Sedimentary rocks form from weathering or layering that takes place over millions of years.
4. Metamorphic Rocks
Rocks that change due to intense heat or pressure in the Earth's crust are called metamorphic rocks.
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