Definitions for "Xenolith"
Fragments of rocks of extraneous origin that have been picked up by magma and are therefore foreign to the igneous rocks in which they occur.
(geology) a piece of rock of different origin from the igneous rock in which it is embedded
a foreign rock fragment, some of which are formed deep within the semi-molten core of the earth, and subsequently carried to the surface as part of a magmatic eruption
Keywords:  silica, lava, deficient, hardening
a silica deficient lava and hardening