User blog comment:Mrob27/Molycastle/@comment-4829477-20121015121039/@comment-4583259-20121016083616

Yeah, I think I used every single material somewhere, including all the alchemy materials. In addition to the obvious Molybdenum, I have Oil Stone roofs on some of the houses, Silver for the foundation stringer walls, Carbon for the city walls and turrets, Snow in a bunch of places. I use all the common materials too, all for specific purposes. Partly this is to make it less confusing (like if I see silver while digging I know I've reached a wall), and partly to make it look a little more interesting.

Obsidian is black right? I guess you could use Dark Stone (graphite) and pretend it's obsidian...