Much earthy material-Gangue-containing silica and silicates is always found with iron ores.
"An Introduction to Chemical Science"
R.P. Williams
Garrick, a Huguenot name, is Fr, Gangue, an old word for heath.
"The Romance of Names"
Ernest Weekley
Hence the elimination of the worthless "Gangue" by concentration of the iron particles associated with it, seemed to be the only solution of the problem.
"Edison, His Life and Inventions"
Frank Lewis Dyer and Thomas Commerford Martin