Igneous Rock Chapter 4 Section 2

Igneous rocks Igneous rocks are classified by their origin, texture, and mineral composition

Origin and Texture Extrusive rock- rock that forms from lava on or near Earth’s surface - they have small crystals and fine-grained texture due to quick cooling Andesite

Origin and Texture - Some cool so fast that no crystals form and rock has a glassy texture Obsidian

Origin and Texture Intrusive rock – rock that forms from magma beneath Earth’s surface - they have large crystals and a coarse- grained texture due to slow cooling Granite

Mineral Composition Minerals low in silica are dark colored and dense Minerals high in silica are usually light colored and less dense

Uses of Igneous Rock Bridges Statues Fortresses

Uses of Igneous Rock Countertops Gravel Cleaning, polishing, and cutting tools Streets