xenocryst

[zen-uh-krist, zee-nuh-] /ˈzɛn ə krɪst, ˈzi nə-/
noun, Mineralogy
1.
a rock or crystal engulfed by magma and retained as an inclusion in the resulting igneous rock.
Origin
Related forms
xenocrystic, adjective
British Dictionary definitions for xenocryst

xenocryst

/ˈzɛnəˌkrɪst/
noun
1.
a crystal included within an igneous rock as the magma cooled but not formed from it
Word Origin
C20: from xeno- + cryst(al)
xenocryst in Science
xenocryst
  (zěn'ə-krĭst', zē'nə-)   
A crystal foreign to the igneous rock in which it occurs. Xenocrysts usually form during metamorphism. Compare xenolith.