andesite
[an-duh-zahyt]
- a dark-colored volcanic rock composed essentially of plagioclase feldspar and one or more mafic minerals, as hornblende or biotite.
Show More
Origin of andesite
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for andesite
Historical Examples
In the main the lava is an andesite, and is very generally of a porphyritic structure.
Mount RainierVarious
The rocks of which the mountains are composed consist of varieties of andesite.
Volcanoes: Past and PresentEdward Hull
Surface eruption of quartz-porphyry, rhyolite, and andesite.
A later series of small diorite or andesite dikes cut the ore bodies.
The Economic Aspect of GeologyC. K. Leith
The Ochils and other hills of middle Scotland largely consist of andesite.
andesite
- a fine-grained tan or grey volcanic rock consisting of plagioclase feldspar, esp andesine, amphibole, and pyroxene
Show More
Word Origin
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
[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.
Show More
The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.