The Worthless Rock That Surrounds Ores and Stones

This page is the CodyCross answer for the clue below from Hobbies, Group 1412, Puzzle 4 (Car Restoration).

Question is: The Worthless Rock That Surrounds Ores and Stones

and the answer is: GANGUE

Word Meaning:

GANGUE — (mining) The earthy waste substances occurring in metallic ore.

Definitions from Wiktionary.