Obsidian may be found naturally on rare occasions, when there is flowing Water and source Lava blocks nearby. Obsidian is created when flowing water hits a lava "source block"; when water and runoff lava collide, Cobblestone is created. In the Overworld, Obsidian never actually spawns with the chunk, but is created by the environment. In The End, solid pillars of obsidian can be found on the surface. Obsidian can only be successfully mined with a diamond pickaxe.