The Basics About Rocks

The Earth has three main types of rocks: igneous, sedimentary, and metamorphic. Igneous rocks form out of molten magma, then undergo weathering, which disintegrates them to form sediments and soil. Sediments can become cemented back together to form sedimentary rocks. Igneous or sedimentary rocks can also undergo additional heating or high pressure, which partially melts them and transforms them into metamorphic rocks. Finally, all rocks can melt completely back into molten magma.

Types of Igneous Rocks
How Igneous Rocks Form: Bowen's Reaction Series

Mechanical Weathering
Chemical Weathering
What Soil is Made Of and How It Forms