Gold Kryptonite

Pre-Crisis, it permanently removes superpowers from Kryptonians, by destroying the ability of Kryptonian cells to process solar energy. Because it was said to be permanent, this variety was rarely used in Superman stories. Gold kryptonite appears in The Flash #175 and plays a key role in the 1982 limited series "The Phantom Zone". In the Legion of Super-Heroes #293 during "The Great Darkness Saga", it is shown that Element Lad can transmute matter into gold kryptonite. Gold kryptonite's final Earth-1 appearance was the 1986 "Imaginary Story" Superman: Whatever Happened to the Man of Tomorrow?"

Post-Crisis, gold kryptonite has appeared in Adventures of Superman #444 and Superman #22. In Action Comics Annual #11, Metallo mentions that the modern age gold kryptonite in his chest only temporarily removes a Kryptonian's powers. The exact time period is later revealed to be fifteen seconds.

Other Media

Smallville

In Season 10 episode "Luthor", the Earth-2 Lex used gold kryptonite to try killing Clark Luthor. The gold kryptonite was not seen in the episode but it was mentioned that Clark Luthor's L-shaped scar was branded with the kryptonite.

In the episode, Kent, Jonathan Kent of Earth-2 claims that he found gold kryptonite in Smallville. But Jonathan thought the kryptonite was actual gold so that he can buy his old farm back. Emil Hamilton later found about the information of the gold kryptonite which can also take Clark's powers permanently.

In the episode called "Prophecy", Oliver who was under the control of Darkseid digs the ground and finds gold kryptonite. Oliver may use the gold kryptonite to kill Clark or remove his powers permanently. Later in the series finale of Smallville, Oliver receives the gold kryptonite ring from Dessad to take Clark's powers away for good. During the wedding ceremony, Oliver gives the ring to Lois as she's going to put it in Clark's finger. However, Chloe noticed that the ring is made up of gold kryptonite and pushes the ring away to prevent from Clark being powerless.