• synonyms


noun Petrography.
  1. a fine-grained igneous rock having such compact texture that the constituent minerals cannot be detected with the naked eye.
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Origin of aphanite

1860–65; < Greek aphan(ḗs) unseen, hidden, invisible (a- a-6 + phanēs, adj. derivative of phaínein to bring to light, disclose) + -ite1
Related formsaph·a·nit·ic [af-uh-nit-ik] /ˌæf əˈnɪt ɪk/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for aphanitic


  1. any fine-grained rock, such as a basalt, containing minerals that cannot be distinguished with the naked eye
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Word Origin for aphanite

C19: from Greek aphanēs invisible
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

aphanitic in Science


  1. Of or relating to an igneous rock in which the crystals are so fine that individual minerals cannot be distinguished with the naked eye. Aphanitic rocks are extrusive rocks that cooled so quickly that crystal growth was inhibited. Compare phaneritic.
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The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.