andesite

[an-duh-zahyt]

noun

a dark-colored volcanic rock composed essentially of plagioclase feldspar and one or more mafic minerals, as hornblende or biotite.

Origin of andesite

1840–50; named after Andes; see -ite¹

Related formsan·de·sit·ic

[an-duh-zit-ik] /ˌæn dəˈzɪt ɪk/, adjective

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for andesitic

Historical Examples of andesitic

These are characterized by igneous rocks of andesitic nature.
The Avifauna of Micronesia, Volume 3
Rollin H. Baker
The building fronts the west, and is constructed of an andesitic tuff of inferior quality and dark colour.
Encyclopaedia Britannica, 11th Edition, Volume 15, Slice 3
Various
Great masses of granite, syenite and diorite were intruded at this period, and send tongues even into the andesitic tuffs.
Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 5
Various
It is composed of andesitic lavas of the augite type, is pierced by many fumaroles, and has a crater in the solfatara stage.
The Solomon Islands and Their Natives
H. B. (Henry Brougham) Guppy
Amongst them I may mention those of Bougainville Strait, which are composed of andesitic lavas of the hornblende type.
The Solomon Islands and Their Natives
H. B. (Henry Brougham) Guppy

British Dictionary definitions for andesitic

andesite

noun

a fine-grained tan or grey volcanic rock consisting of plagioclase feldspar, esp andesine, amphibole, and pyroxene

Word Origin for andesite

C19: from Andes + -ite 1

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

andesitic in Science

andesite

[ăn′dĭ-zīt′]

A gray, fine-grained volcanic rock. Andesite consists mainly of sodium-rich plagioclase feldspar and one or more mafic minerals such as biotite, hornblende, or pyroxene. It often contains small, visible crystals (phenocrysts) of plagioclase.