Geology Word of the Week: X is for Xenolith

Mafic xenolith, Ontario, Canada, 2002. Photo Credit: Ron Schott.

Note: Sorry for the re-post. This post was lost and then mangled somewhat in the blogger mishap last week. I managed to correct the post, but I had to re-post it under a new day and time.   

def. Xenolith:
A foreign rock inclusion, usually in an igeneous rock.