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 (zĕn′ə-krĭst′, zē′nə-)
A crystal foreign to the igneous rock in which it occurs.

American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


(Geological Science) a crystal included within an igneous rock as the magma cooled but not formed from it
[C20: from xeno- + cryst(al)]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014
References in periodicals archive ?
One grain (Zl), larger and older than the other dated grains, is interpreted as a xenocryst and has a [sup.206]Pb/[sup.238]U age of 423.3 [+ or -] 0.6 Ma.
(2012): Anomalous xenocryst dispersion during tonalite-granodiorite crystal mush hybridization in the mid crust: Mineralogical and geochemical evidence from Variscan appinites (Avila Batholith, Central Iberia).
A second data set comes from a xenocryst in the Orano porphyry, a unit characterized by extensive captured crystals from the Monte Capanne system (Dini et al.
This suggests that some of the phenocrysts that had formed in the rhyolitic magmas were later enclosed (as xenocrysts) within the more mafic one (i.e., as enclaves).
Xenocrysts are composed of orthoclase and reach 2-3 cm in size.
Lavas from the northwestern knoll are fresh, slightly ollvine-phyric lavas with abundant vesicles and rare, partially resorbed plagioclase xenocrysts. The 1970 sample from the northwestern knoll is transitional basalt, plotting on the Hawaiian tholeiite-alkalic basalt boundary, whereas the 1994 lava is tholeiitic basalt with a higher Si[O.sub.2] content (Fig.