How do intrusive rocks differ from extrusive rocks?

Intrusive rocks and extrusive rocks are both types of igneous rocks, formed from the cooling and solidification of magma or lava. The primary difference lies in where this cooling and solidification occurs.1

Intrusive Rocks:
* Formed from magma that is forced into older rocks deep within the Earth's crust.2
* Solidify slowly below the Earth's surface.2
* This slow cooling allows for the formation of larger mineral crystals, resulting in a phaneritic (coarse-grained) texture.3
* They may later be exposed at the surface through erosion.2

Extrusive Rocks:
* Formed from magma that erupts onto the Earth's surface as lava or is ejected as pyroclastic debris.45
* Cool and solidify rapidly on the surface.4
* This rapid cooling results in fine-grained (aphanitic) or glassy textures, as minerals have little time to grow.43
* Examples include lava flows and fragmented volcanic material.45