Igneous Rocks Facts

Igneous Rocks Facts
Rocks are classified by the way they form. Igneous rocks are those that form when magma cools and hardens. This process can occur on the Earth's surface or underground. The exact location of the formation of the rock determines the type of igneous rock it is.
Interesting Igneous Rocks Facts:
When magma rises to the surface of the Earth and hardens, it forms extrusive igneous rock.
Extrusive igneous rock tends to be glassy in texture because their formation occurs very rapidly.
Examples of extrusive igneous rock include pumice and basalt.
Pumice is an extrusive igneous rock used in many products such as toothpaste, cement, and cosmetic products
Basalt is an extrusive igneous rock used in constructing buildings and statues.
Extrusive rocks are also referred as volcanic rocks because volcanoes are important in their formation.
When magma cools and hardens below the Earth's surface, an intrusive igneous rock forms.
Because the process of the formation of intrusive igneous rock occurs slowly, these rocks tend to have a grainy texture.
Examples of intrusive igneous rock include granite and gabbro.
Granite is an intrusive igneous rock used as for making gravestones, statues, and countertops because it is very durable.
Gabbro is an intrusive igneous rock that often contains profitable amounts of gold, chromium, and silver.
Plutons are bodies of intrusive rock which are usually composed of granite.
When intrusive rocks form huge bodies such as those found in the core of mountains, they are referred to as batholiths.
Ninety-five percent of the Earth's crust is made of igneous rock.
There are over 700 different kinds of igneous rocks that have been identified.

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