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Magma is molten rock that is deep underground.
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Courtesy of Boise National Forest

Magma

If you could travel to the center of the Earth, you would find that it gets hotter and hotter as you travel deeper. The heat is naturally produced when radioactive elements break apart. Within the Earth’s mantle layer it is hot enough that much of the rock has melted, turning it into a liquid that we call molten rock.The molten rock is called magma. Magma is so hot that it glows white and is so bright that you’d need sunglasses to look at it! If it flows into an area underground that is less hot, it cools, becomes yellow, and then increasingly deeper shades of red. As it cools slowly, minerals crystallize from the melt forming intrusive igneous rocks like granite.

If magma finds a crack in the Earth and comes to the surface, it is called lava and cools to form extrusive igneous rocks like basalt.


Last modified June 17, 2003 by Lisa Gardiner.

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TES XXVI, 3 fall 2010 The Fall 2010 issue of The Earth Scientist, focuses on rocks and minerals, including articles on minerals and mining, the use of minerals in society, and rare earth minerals, and includes 3 posters!

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