In context|geology|lang=en terms the difference between igneous and xenolith
is that igneous is (geology) resulting from, or produced by, the action of great heat; with rocks, it could also mean formed from lava/magma; as, granite and basalt are igneous rocks while xenolith is (geology) any piece of rock having a different origin to that of the igneous rock in which it is found.
As an adjective igneous
is pertaining to, having the nature of fire; containing fire; resembling fire; as, an igneous appearance.
As a noun xenolith is
(geology) any piece of rock having a different origin to that of the igneous rock in which it is found.
igneous
English
Adjective
(
en adjective)
Pertaining to, having the nature of fire; containing fire; resembling fire; as, an igneous appearance
(geology) Resulting from, or produced by, the action of great heat; with rocks, it could also mean formed from lava/magma; as, granite and basalt are igneous rocks
xenolith
Noun
(
en noun)
(geology) any piece of rock having a different origin to that of the igneous rock in which it is found