I am not 100% sure, but I believe that items cannot be transferred through Pokémon Bank. This is probably because some items, such as exp. share, don't work the same way anymore. It probably has a different item ID, so if you transferred one, it might become another item. However, according to the bulbapedia link Dark_Breeder answered me with, there is a fairy gem in the code. If you haven't heard about the new region rumors, check out JWittz or Marriland on youtube, but I think that if those rumors are true, the gems will be in those games.