Minecraft wiki entry for Diamonds, associated text: If the table doesn't offer any of the desired enchantments, the player must enchant something to get a new selection. If one of the enchantments on offer is halfway interesting (that is, it might be useful later), players might then enchant it onto an iron pick or a book. Alternatively, players can do a one-level (minimum) enchantment on a junk item like a wooden shovel. They can then use a grindstone to reclaim some of the experience used for the enchantment.