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 andesite

Historical Examples of andesite

In the main the lava is an andesite, and is very generally of a porphyritic structure.
Mount Rainier
Various
The rocks of which the mountains are composed consist of varieties of andesite.
Volcanoes: Past and Present
Edward Hull
Surface eruption of quartz-porphyry, rhyolite, and andesite.
History and Comprehensive Description of Loudoun County, Virginia
James W. Head
A later series of small diorite or andesite dikes cut the ore bodies.
The Economic Aspect of Geology
C. K. Leith
The Ochils and other hills of middle Scotland largely consist of andesite.
The New Gresham Encyclopedia. Vol. 1 Part 2
Various

British Dictionary definitions for andesite

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

andesite 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.