Where does “escoria” come from?

escoria (Spanish) comes from Latin scōria, from Ancient Greek σκωρία, from Ancient Greek σκῶρ, from Proto-Hellenic skṓr, from Proto-Indo-European sḱṓr, from Proto-Indo-European sóḱr̥, from Proto-Indo-European -r̥ — Derives nouns from roots, frequently mass nouns.

escoria (Spanish): slag; scum; scoria