Minecraft wiki entry for Before_1.8, associated text: The most important concept for using an anvil is the Base Value of an item, figured in experience levels. Other than combining with enchanted books, any change made to an item will cost its Base Value plus costs for the change. An item's Base Value is the sum of the costs of its enchantments, plus a charge for the number of its enchantments. Note that the item's material does not affect its base cost, nor does the order of its enchantments. An unenchanted (or unenchantable) item has Base Value 0.