gangue

noun

ˈgaŋ 

: the worthless rock or vein matter in which valuable metals or minerals occur

Word History

Etymology

borrowed from French, going back to Middle French, borrowed from German Gang "walk, course, passageway, mineral vein or seam," going back to Old High German gang "walk, course" — more at gang entry 1

First Known Use

1809, in the meaning defined above