Lex Luthor made a Green Kryptonite ring by putting a Green Kryptonite emerald into a ring, giving him the power to radiate Green Kryptonite radiation in their presence and killing them.
Background[]
After Black Kryptonite split apart Lex's good side and bad side, the side that had darker impulses Alexander used a Green Kryptonite ring. During their Arctic confrontation, Lex likely wore a Green Kryptonite ring under his glove because he found out Clark's secret. Lex was wearing the Green Kryptonite ring in the truck when he was spying on Clark and Lang, and Oliver took the ring after he killed Lex with a Toyman super bomb. Oliver used the ring against Parasite who had absorbed Clark's powers and was about to kill him but Clark stopped him and got his powers back.
Notes[]
It's possible the green meteor rock Dr. Steven Hamilton gave Lex was what he made the Green Kryptonite ring out of, seeing as that was the first meteor rock he ever owned, other than when he temporarily had Lana's necklace.
