- a granular plutonic rock composed largely of labradorite or a more calcic feldspar.
Origin of anorthosite
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for anorthosite
Historical Examples of anorthosite
In Canada great portions of the eastern portion of the Dominion are formed of gabbros, norite, anorthosite and allied rock types.
- a coarse-grained plutonic igneous rock consisting almost entirely of plagioclase feldspar
Word Origin for anorthosite
C19: from French anorthose (see an-, ortho-) + -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
- An igneous rock consisting almost entirely of plagioclase feldspar, especially the labradorite variety. Anorthosites have been identified among rock samples collected from the Moon.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.