BLACK DIAMOND ORE: (can be found at layer 16 and below, if you smelt it is turned into Black Diamond)
So you can craft Black Diamond. Or you can smelt the black diamond ore into one Black Diamond. With 1 diamond in the center and a obsidian block on each side.
With it you can create Tools like you normaly would do.
Now you can make armor too. (like you normaly would)