The Only thing That Can Break Obsidian Is A Diamond Pickaxe. :3
Nothing in vanilla aside from repeatedly hitting and creative mode can break obsidian. No amount of wither or TNT will break it.
You may only mine Obsidian with a Diamond Pickaxe.
You need a Diamond pickaxe to mine Obsidian.
You need an iron pickaxe or better to mine gold. Ironically, a gold pickaxe will not be able to mine itself.
you can use a iron pickaxe to mine it as this can mine every ore in minecraft