glass-like slag
111rock wool — n. a fibrous material that looks like spun glass, made from molten rock or slag by passing a blast of steam through the fluid; mineral wool: it is used for insulation, esp. in buildings …
111rock wool — n. a fibrous material that looks like spun glass, made from molten rock or slag by passing a blast of steam through the fluid; mineral wool: it is used for insulation, esp. in buildings …