Here's a breakdown:
* Magma: Molten rock found beneath the Earth's surface.
* Lava: Magma that has erupted onto the Earth's surface.
The rapid cooling and solidification of lava on the surface creates the characteristic features of extrusive rocks, such as:
* Fine-grained texture: The rapid cooling doesn't allow crystals to grow large.
* Porous texture: Gases trapped in the lava can create holes (vesicles).
* Glassy texture: Some lava cools so quickly that crystals don't form at all, resulting in a glassy texture.
Examples of extrusive rocks include:
* Basalt: A dark-colored, fine-grained rock formed from mafic lava.
* Rhyolite: A light-colored, fine-grained rock formed from felsic lava.
* Obsidian: A black, glassy rock formed from rapidly cooled felsic lava.
* Pumice: A very porous rock formed from frothy lava.
