The rocky and siliceous non-metallic impurities associated with an ore are collectively called

1. Ores are mixed with earthy, rocky and siliceous impurities. 2. These undesired impurities are collectively called **gangue** (or matrix). 3. A **flux** later combines with the gangue to form a fusible **slag**; **matte** is a mixture of $Cu_2S$/$FeS$. _Source: Samacheer Kalvi Class 12 Chemistry Vol.1, Unit 1 'Metallurgy', §1.2_