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A gray, fine-grained volcanic rock consisting chiefly of plagioclase feldspar and one or more mafic minerals.

[After the Andes.]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(ˈændɪˌzaɪt) or


(Geological Science) a fine-grained tan or grey volcanic rock consisting of plagioclase feldspar, esp andesine, amphibole, and pyroxene
[C19: from Andes + -ite1]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈæn dəˌzaɪt)

a dark volcanic rock composed essentially of plagioclase feldspar and one or more mafic minerals.
[1840–50; after the Andes; see -ite1]
an`de•sit′ic (-ˈzɪt ɪk) adj.
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.


A dark, fine-grained rock, taking its name from the Andes Mountains.
Dictionary of Unfamiliar Words by Diagram Group Copyright © 2008 by Diagram Visual Information Limited
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.andesite - a dark grey volcanic rockandesite - a dark grey volcanic rock    
igneous rock - rock formed by the solidification of molten magma
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
commented: "Based on the size and number of vein intersections in the near surface drilling in the andesites, our exploration team has felt that we have found a very large system.
The hole cut 30.10 m of vein breccia and strongly silicified and veined andesites and granodiorite from 126.65 to 156.75 m.
It is volcanogenic in nature and occurs as intercalations with andesites of Sinjrani volcanics.
The ground geophysical survey revealed anomalies close to the surface, with evidence of intense hydrothermal alteration in andesites and rhyolites hosting Au mineralized quartz stockwork zones, concluded the company.
The results presented here include analyses of unaltered host rocks (andesites), analyses of fumarolic sulfur, analyses of sulfur leachates, and the SEM-EDS analyses of rare mineral inclusions in sulfur.
These high-degree, crust-derived partial melts are the source of tholeiitic andesites and basalts that cause summit eruptions at volcanoes in the NE Japan arc.
The andesites of Noorabad ophiolite in hand specimen and thin section have phenocrysts of plagioclase in a groundmass of clinopyroxene and amphibole minerals.
Basalts and basalt andesites. These are equigranular rocks, mainly with doleritic textures but in some cases with microlithic or fluidal microlithic textures.