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Line 1: − Rock that forms from molten rock.<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref>+ − + − <references/>+ + + + + + + + + + + + + + + + + + + + + + +
merge from Igneous Rock
'''Igneous rocks''' are formed when molten [[rock]] is either ejected directly on to the earth's surface ([[extrusive rock]]) or pushed up near the surface and cools beneath it ([[intrusive rock]]). Molten rock beneath the earth's crust is called [[magma]]; when magma is ejected throught the crust it is called [[lava]].
==References==
Most igneous rocks are composed of an interlocking [[mosaic]] of [[crystal]]s. Lava rocks are often riddled with air holes.
==Extrusive Igneous==
Crystals are generally small, often microscopic.
*[[Obsidian]]
*[[Basalt]]
*[[Pumice]]
==Intrusive Igneous==
Crystals are generally large and visible to the naked eye. Intrusive igneous rocks are the source of many [[gemstone]]s.
*[[Granite]]
*[[Gabbro]]
*[[Granite Porphyry]]
Kavanaugh, Pocket Naturalist
==Sources==
*Kavanaugh, James. ''Pocket Naturalist - Geology - An Introduction to familiar Rocks, Minerals, Gemstones & Fossils'', Waterford Press: Arizona (2000)
[[category:Igneous rocks]]