Rocks and Their Types

Core concept

Igneous rocks form from cooled and solidified magma or lava, like granite (cooled slowly underground) or basalt (cooled quickly from lava).

How it works

Sedimentary rocks form from compacted layers of sediment over long periods, like sandstone or limestone, often containing fossils.

Why it matters

Metamorphic rocks form when existing rocks are transformed by intense heat and pressure, like marble (from limestone) or slate (from shale).

Key detail

The rock cycle shows how rocks continuously transform between these three types over geological time through various processes.