scoriaceous

adj

1. Of, relating to, or producing scoria; composed of scoria.

   “On the further side it is more elevated, of a bare and desolate aspect, with a slight depression marking the position of the crater. From this part descends a black scoriaceous tract; very rugged, and covered with a scanty vegetation of scattered bushes as far down as the sea. This is the lava of the great eruption near a century ago, and is called by the natives "batu-angas" (burnt rock).”