When a item like diamond is renamed, it won't appear as usable on a crafting table. Simplified, it's useless. Tested only with diamonds until now. More simplified explanation: renaming a diamond makes it useless as in you can't craft anything with it. Not sure if it's a bug or is intentional.
Comments 2
Cleaning up old tickets: This ticket has not been updated recently (~1 year+) so is being closed as Cannot Reproduce. If you feel this is still a valid issue then please comment, or create a new ticket following the Issue Guidelines.
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Renamed items still retain their usefulness. The crafting book doesn't pick up on renamed items because changing the name changes the NBT of the item and the crafting book is looking for specific (unnamed, normal) items to use.