Here's why:
* Igneous rocks are formed from the cooling and solidification of magma (molten rock) or lava.
* Extrusive refers to rocks that form on the Earth's surface, as opposed to intrusive rocks that form underground.
Some common examples of extrusive igneous rocks formed from lava include:
* Basalt: A dark, fine-grained rock often found in lava flows.
* Rhyolite: A light-colored, fine-grained rock rich in silica.
* Andesite: An intermediate rock in composition and color between basalt and rhyolite.
* Scoria: A dark, vesicular rock with many holes formed by escaping gases.
* Pumice: A very light and porous rock formed from frothy lava.
