Yeah, but is it valuable? Like, is there a stone economy in Minecraft similar to the gold economy in WoW?
Not even remotely. 90% plus of the blocks in the world are stone/cobble. I find myself dumping entire stacks (64 blocks to a stack) of them into lava or in random holes.
Minecraft does have Gold, Iron, and Diamonds. Diamonds are /very/ valuable, and quite rare. Some other materials can only be found in "The Nether" which is a hell like place with extra monsters and death traps, much harder to survive there.