It's true, we could break "Building Materials" out into their own category -- that would make a lot of sense.
Then have common and uncommon resources... or even ingredients.
EDIT: Okay, I added a new category there for it, and that's my new vote for myself, personally. Building Materials, Common Ingredients, and Uncommon Ingredients.
By the by, Common/Uncommon/Rare has those CCG/TCG connotations, and Common/Uncommon is more accurate than Common/Rare in that sort of context. That's what made me think of it.