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Lionel Luthor duplicates the key.

"The composition was unique. There's nothing like it on Earth, with one exception: The meteor rocks found here in Smallville. So I have fashioned my own key. It's identical in every detail."Lionel Luthor, to Clark Kent, Exodus

The kryptonite key, identical to the Key, was created by Lionel Luthor to put into the keyhole in the cave wall inside the Kawatche Caves. He created it out of kryptonite because, as he explained to Clark Kent, the original key was made out of a metal alloy close in composition to the meteor fragments.


Clark places the kryptonite key in the octagonal slot of his ship.

The Kryptonite Key was identical to the original Key in terms of its dimensions and the Kryptonian symbols that adorned it. However it was translucent green in colour and glowed unusually brightly in Clark's presence.


Lionel Luthor created this key and stored it in a lead box within the Kawatche cave but Clark stole it to destroy his spaceship and therefore the Kryptonian artificial entity programmed with the brainwaves of his biological father Jor-El. Once he placed the kryptonite key into the slot where the real key was supposed to be, a viral growth appeared on the exterior of the ship as it floated into the air. The ship then exploded, unleashing an energy wave that caused Jonathan Kent's truck to roll several times and triggered Martha Kent's miscarriage of her unborn child. The kryptonite key was destroyed along with the ship although Lionel's enduring desire to create another duplicate was shown when he proposed melting down the Starblade to construct a second key. The fact that Lionel abstained from creating a second Kryptonite key, with the all too available meteor rock and schematics of the original Key's design, implies that he might have, through experimentation, become aware of the Kryptonite's detrimental effects on Kryptonian technology.

Powers and abilities

  • The Kryptonite key was designed to access Kryptonian technology akin to the original Key however its properties caused Kal-El's craft to implode. One can also assume that the kryptonite key may well have had a similarly destructive effect on the technology embedded in the Kawatche cave wall if it had ever been inserted.
  • The Key appeared to produce an unusually large amount of radiation as was shown by Clark's immediately severe reaction to it despite its small size, suggesting it was made out of refined Green kryptonite.

Kryptonite in Smallville
Types Natural: GreenRedBlueGold kryptonite • Processed: BlackSilverGemstoneClear kryptonite
Effects Meteor infectionPsychosisMeteor freaks
Objects BulletCageHandcuffsHeartKeyRingNecklaceVictory ring
Other KryptonMeteor showers (1989, 2005) • Lead (box) • Appearances of Green K (usages)