Igneous rocks main content.

Igneous rocks

Part of Hall of Planet Earth.

Igneous rocks

Exhibition Text

Igneous rocks solidify from molten rock (called magma within the Earth and lava on the surface). They are identified by mineral content and texture — the size and shape of their mineral grains.

Texture is controlled by the rate of cooling: magma that cools slowly deep in the Earth forms rock with large crystals, and lava that cools quickly on the surface forms fine-grained rock.

For Educators

Topic: Earth Science

Subtopic: Earth Formation/Evolution