[ an-duh-zahyt ]
/ ˈæn dəˌzaɪt /


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 forms

an·de·sit·ic [an-duh-zit-ik] /ˌæn dəˈzɪt ɪk/, adjective Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for andesitic

British Dictionary definitions for andesitic


/ (ˈændɪˌzaɪt) /


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

Science definitions for andesitic


[ ăndĭ-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.
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