Kryptonite ring
From Smallville Wiki
The kryptonite ring is a piece of jewelery constructed by Lex Luthor to protect himself from approaching Kryptonians. The ring is a square shaped ring covered with a kryptonite gem. The ring has an L underneath the gem, to signify the name Lex or Luthor.
[edit] Season Four
The first kryptonite ring was when Lex was experimenting with kryptonite and turned it into black kryptonite with it splitting his body into two separate beings that represented his two personalities. The evil personality, Alexander, created a kryptonite ring to defend himself against Clark Kent so that he wouldn't be able to approach him without pain.
[edit] Season Eight
When Lex returned from the Fortress of Solitude after his duel with Clark, he was severely injured and was in constant care of life support machines and wore a kryptonite ring that bore the Luthor family emblem which was engraved within the kryptonite. After Oliver planted one of Winslow Schott's bombs under Lex's truck, he was not found and presumed dead. Then Oliver collected Lex's kryptonite ring as a memento.
