Definition of "andesite" [an•des•ite]

• A gray, fine-grained volcanic rock, chiefly plagioclase and feldspar. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "A third type of magma, called andesite, named after the Andes Mountains where it is often found, is composed of a mixture of both felsic and mafic magma."
• "(FeCO3), used as a pigment, and also found in the Kirtland shale; and various metamorphic and igneous rocks (such as andesite, schist, gabbro, slate, and olivine), which could have been picked up in the river"
• "The Volcanic Mid-Elevation Forests ecoregion occurs at elevations of about 7500 to 10,000 feet and is composed of igneous rocks of andesite and basalt."