Unlike later generations, Kadabra is no exception; a Kadabra holding an Everstone is prevented from evolving, like any other Pokémon.
In this generation only, trade evolutions are affected by the held item loss glitch: If Kadabra, Machoke, Graveler, or Haunter is traded while holding any item (including an Everstone), that Pokémon will evolve and its held item will be permanently lost.
Generation IV onwards
This section is incomplete. Please feel free to edit this section to add missing information and complete it. Reason: Test if the Generation III glitch is still present in Generation IV onwards - that is, if Everstone and other held items are permanently lost when a Pokémon evolves by trade
If either Karrablast or Shelmet holds an Everstone when traded for the other, neither can evolve.
This move effect may be in need of research. Reason:Does the Everstone work if held by a female Pokémon bred with Ditto in E/DPPt? What happens if both parents hold an Everstone in HGSS/BW? Does the Everstone affect the regional form of a Pokémon if held by a male parent in a male/female pair? What if both parents hold an Everstone but have different regional forms? You can discuss this on the talk page.
If held by a Pokémon that has regional forms in the Pokémon Nursery, bred Pokémon will be the same regional form as the parent regardless of the region they are bred in. (Normally, hatched Pokémon are always in the form corresponding to the region in which they were bred.)