Igneous sedimentary metamorphic

Science

Definition

The three main types of rocks classified by how they form. Igneous rocks form from cooled magma or lava, sedimentary rocks form from compacted layers of sediment, and metamorphic rocks form when existing rocks are changed by heat and pressure.

Examples

  • Granite (igneous) forming slowly underground from cooling magma
  • Limestone (sedimentary) forming from accumulated marine shells and calcium carbonate
  • Marble (metamorphic) forming when limestone is subjected to intense heat and pressure

Related Terms

Rock cycle Mineral identification Erosion and deposition Plate tectonics

Study This Concept

Practice igneous sedimentary metamorphic with free review games in these units:

Earth Science Unit 1: Minerals and Rocks