Rocks (Book): Three Main Categories of Rocks

This chapter discusses the rock cycle and each of the three major types of rocks that form on Earth. Separate sections cover igneous, sedimentary, and metamorphic rocks individually.

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TYPE OF ROCKS

Three Main Categories of Rocks

Geologists group rocks based on how they were formed. The three main kinds of rocks are:

Igneous

Sedimentary

Metamorphic

Rocks can be changed from one type to another, and the rock cycle describes how this happens.