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Igneous Rock

Igneous rocks are those which are formed in the process of volcano formation, that is by the melting and remelting of the Earth's crust. In other words, these rocks are created from material of the Earth's interior. Igneous rocks are also known as volcanic or plutonic rocks, named for the gods Vulcan and Pluto (gods of fire and the netherworld), and refer to the molten state of the earth.

Igneous rocks come in two forms,

The building blocks of igneous rock are silicate rocks. The most important group of igneous rocks are the basaltic rocks: gabbros and basalts. The second most important group of igneous rocks are the granitic rocks: granite and rhyolite. The difference between the two groups is in silica content. A basalt is about 53% SiO2, granite 73%.


This image shows a type of igneous rock called granite.
Click on image for full size version (92K JPG)
Image from: C. Alexander

Go to a listing of Rocks by mineral group

Rock Image Archive


Igneous Rock

Igneous rocks are those which are formed in the process of volcano formation, that is by the melting and remelting of the Earth's crust. In other words, these rocks are created from material of the Earth's interior. Igneous rocks are also known as volcanic or plutonic rocks, names which alluding to the gods Vulcan and Pluto (gods of fire and the netherworld), and refer to the molten state of the earth.

Igneous rocks come in two forms,

The building blocks of igneous rock are silicate rocks. The most important group of igneous rocks are known as the basaltic rocks: gabbros and basalts. The second most important group of igneous rocks are known as the granitic rocks: granite and rhyolite. The difference between the two groups is in silica content. Granite has a larger amount than basalt.


This table shows the different kinds of igneous rocks.

Go to a listing of Rocks by mineral group

Rock Image Archive


Igneous Rock

Igneous rocks form during volcano formation, that is by the melting of the Earth's crust. In other words, these rocks are created from material of the Earth's interior. Igneous rocks are also known as volcanic or plutonic rocks.

Igneous rocks come in two forms,

The building blocks of igneous rock are silicate rocks, and a common igneous rock is granite.


This table shows the different kinds of igneous rocks.

Go to a listing of Rocks by mineral group

Rock Image Archive



Last modified January 15, 1998 by the Windows Team

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