How are rocks formed?

Rocks are so common that most of us take for granted—cursing when we hit them while gardening or trip over them. But have you ever wondered how they are formed? There are three main types of rocks: sedimentary, igneous, and metamorphic. These rocks are formed by physical changes—such as melting, cooling, eroding, compacting, or deforming—that are part of the rock cycle.

How are rocks formed?

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