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Lex Luthor in front of a display of Kryptonite and holding green Kryptonite.
From a panel in Action Comics Annual #10, 2007. Art by Gary Frank.
The Adventures of Superman
|In story information|
|Element of stories featuring||Superman|
Kryptonite is a fictional material from the Superman mythos — the ore form of a radioactive element from Superman's home planet of Krypton. It is famous for being the ultimate natural weakness of Superman and most other Kryptonians, and the word Kryptonite has since become synonymous with an Achilles' heel —the one weakness of an otherwise invulnerable hero.
Originating in the Superman radio show series, the material is usually shown as having been created from the radioactive remains of Superman's native planet Krypton, and generally has detrimental effects on Superman and other Kryptonians. The name "Kryptonite" covers a variety of forms of the substance, but usually refers to the most common "green" form.
Original versions 
A forerunner of the Kryptonite concept was the unpublished 1940 story "The K-Metal from Krypton", by Superman co-creator Jerry Siegel. The K-metal in the story was a piece of Krypton which robbed Superman of his strength while giving humans superhuman powers, a plot point which decades later made its way into the TV series Smallville. Jerry Siegel also stated that the naming of the planet Krypton was taken from the element Krypton due to the common denominators of high density and viscosity between the two.
"Kryptonite" was introduced in June 1943 on the Superman radio series, in the story arc "The Meteor from Krypton". It was used as both a plot device and as a means to allow Superman's actor, Bud Collyer, to take occasional time off. The substance played a part in at least one major plot-line during the course of the program.
It was not until 1949 that comic book writers incorporated Kryptonite into their stories, as both a convenient danger and weakness for Superman and to add an interesting element to his stories. Pioneering female editor Dorothy Woolfolk claims she brought Kryptonite to the comics. She told the Florida newspaper Today in August 1993 that she had found Superman's invulnerability dull, and that DC's flagship hero might be more interesting with an Achilles' heel such as adverse reactions to a fragment of his home planet.
Kryptonite, in its first comic appearance (Superman vol. 1, #61, in 1949), was quite rare. It came to earth inside a single meteorite from the exploded planet Krypton. Superman captured the two small pieces of Kryptonite, one from a fake swami (pretending to "hex" Superman with it) and another he purchased from a jewelry store, and threw them into Metropolis' river. Over time, Kryptonite was depicted as being so abundant that many ordinary criminals kept a supply as a precaution against Superman's interference. In several accounts, it was explained that the explosion of the planet Krypton had opened a "dimensional warp" (similar to a wormhole in modern theoretical physics) which allowed the vehicle carrying the young Kal-El to reach Earth in a relatively brief time, and a large amount of planetary debris had also passed through this "warp" and emerged near Earth at virtually the same time, accounting for the seemingly improbable abundance of Kryptonite material and its availability to Superman's enemies. Science fiction writer Larry Niven has tongue-in-cheek theorized that, based on such abundance, Krypton was actually a Dyson sphere with a surface hundreds of times that of a mere planet.
Kryptonite is most commonly depicted as green in coloring, with a few exceptions; it was red in its first appearance in Superman #61 (November 1949). When Superman followed the time trail of a piece of red rock that weakened him, he was able to trace his origin back to Krypton for the first time. Other colors of Kryptonite, having different effects, began to show up frequently beginning in late 1950s comics, reaching a peak in appearances in 1960s Superman series. (See below for further detail on Kryptonite variations.)
In an effort to reduce the use of Kryptonite in Superman storylines, all known Kryptonite on Earth was transmuted into "k-iron" in a 1971 storyline titled "The Sandman Saga", though Kryptonite could still be synthetically manufactured by a variety of known and unknown means, and additional material left over from the destruction of Krypton would continue to fall from space.
Post-Crisis versions 
Upon the John Byrne reboot of the Superman mythos after Crisis on Infinite Earths, Kryptonite was made much rarer in the DC Universe and many of the multicolored varieties were eliminated. The only sample of Kryptonite on Earth was a single fist-sized chunk, caught in the tail of the infant Kal-El's rocket and carried to Earth along with him upon the explosion of Krypton. This sample had been found by the scientist who resurrected John Corben as Metallo, powering the cyborg with the alien matter in a paranoid attempt to save the world from Superman, as a mistranslation of a message from Jor-El caused the scientist to conclude that Superman was the leader of an alien invasion force. Metallo was soon kidnapped and his power source forcibly removed by Lex Luthor who, after discovering its debilitating effects on Kryptonians, created a ring with a Kryptonite gem to keep Superman at bay. This backfired badly on Luthor, as long-term exposure to Kryptonite radiation from the ring gave him cancer, leading to the amputation of his hand and then apparent death (although he was able to have his brain transplanted into a cloned body). Superman took possession of the ring and entrusted it to Batman, stating that he was the only person he could trust with the ability to kill him if necessary; Batman subsequently kept the ring available whenever circumstances required him and Superman to work together.
Red Kryptonite made a brief appearance during this era, where it had the effect of rendering Superman permanently powerless. However, the red Kryptonite and resulting powerlessness turned out to be a magical illusion created by Mister Mxyzptlk, with Superman's powers being restored once he learned of Mxyzptlk's involvement in accordance with the imp's usual restrictions. In time, through the use of Batman's notes, Ra's al Ghul was able to fashion a synthetic red Kryptonite, this version turning Superman's skin transparent and leaving him almost exploding with power as the sunlight that gave him his powers was sent directly into his muscles without being filtered by his skin.
The amount of Kryptonite on Earth increased dramatically, carried down to the planet's surface in a meteor shower[clarification needed] that accompanied the rocket that brought Kara to Gotham City. Superman-friendly corporations, such as Wayne Enterprises and Kord Industries take it upon themselves to round up this influx of Kryptonite, but much of it goes into illicit circulation or is stolen from holding facilities.
In the recreated universe, Kryptonite is in such abundance that it again becomes easily available to ordinary criminals and crooks. Following orders issued by Lex Luthor and Lana Lang, LexCorp starts stockpiling and selling it to government facilities and weapon makers. Superman and Batman embark on a mission to rid Earth of Kryptonite, a mission that almost fails when the cornered Lana Lang, attempting to protect LexCorp investments, launches a large number of dirty Kryptonite warheads, tainting the whole Earth atmosphere. Hiro Okamura builds and frees a storm of nanobots devised to capture and deactivate the tiniest fragments of Kryptonite.
Once again, as in the 1971 storyline, virtually all Kryptonite is destroyed. The remaining fragments are wrapped in lead and hurled into the sun by Superman himself, except for one fragment, which Superman gives to Batman. It is later revealed that Batman has acquired a fair amount of every variety of the alien material, keeping his samples in the Batcave.
By the events told in the New Krypton storyline however, several Superman villains, like Metallo and Reactron, have acquired some Kryptonite samples to use against the Kryptonians on Earth. Lex Luthor and Sam Lane, working for the government, have a cache of the precious material too.
Forms of Kryptonite 
Composition of Kryptonite 
The composition of Kryptonite varies depending on the source material.
In the Silver to Bronze Age stories, as well as in the "Green, Green Glow of Home" episode of Lois & Clark New adventures of Superman, Kryptonite is a stable transuranic element (element 126) that finally decays to iron.
However in Superman III (1983) it is said that Kryptonite is an alloy made up of 15.08% plutonium, 18.06% tantalum, 27.71% xenon, 24.02% promethium, 10.62% dialium, 3.94% mercury, and 0.57% of an unknown substance. A Post-Crisis story in Action Comics #591 (Aug 87) also made Kryptonite an alloy.
The various known forms of Kryptonite in the Superman media:
|Green Kryptonite||In various stories, Superman is shown to have become immune to the effects of green Kryptonite due to either repeated non-fatal exposure, continuous long-term absorption of solar radiation, or extremely high short-term exposure to the sun.
Green Kryptonite is typically shown to have no short-term effects on humans or non-superpowered Kryptonians. However, in post-Crisis continuity, long-term exposure can cause radiation poisoning in Humans, similar to long-term exposure to Uranium.
In Smallville, high levels of green Kryptonite radiation can cause normal Humans to mutate and acquire superhuman abilities (these mutants are usually called "meteor freaks"), although an outside catalyst (such as a strong electrical charge or a meteor shower) is usually required. In the episode "Leech," it is shown that if an electrical current is combined with green Kryptonite radiation it can cause the transference of a Kryptonian's powers to a human. In the episode "Void," Kryptonite injections cause near-death experiences in Humans. After Clark is injected with Kryptonite and apparently dies, Chloe reports "actually dying neutralizes the Kryptonite in your system".
Green Kryptonite does have beneficial uses to Kryptonians, however. In Smallville, Green Kryptonite is used to counter the effects of any other form of Kryptonite that may enter a Kryptonian's system, for example a kiss with red Kryptonite laced lipstick or Gem Kryptonite dust in the eyes. In Lois and Clark, a green Kryptonite bullet is also used to bring Superman back in control when his powers become over-amped by red Kryptonite and a sample of Kryptonite was used to starve out a Kryptonian virus Superman was introduced to by Mrs. Church. In an episode of Superman: the Animated Series, a wounded Supergirl required surgery to preserve her life. As regular scalpels are unable to penetrate the skin of super-powered Kryptonians (or in this case, a being from the same solar system as Krypton), Kryptonite-enhanced equipment was used to do the operation.
Green Kryptonite, being radioactive, has been used as an energy source to power reactors in power stations. The supervillain Metallo uses green Kryptonite to power his cyborg body.
In both the post Crisis comics and the cartoon series Justice League Unlimited it is shown that prolonged exposure to Kryptonite causes Humans to contract cancer. Lex Luthor gets cancer due to his constant exposure.
|Red Kryptonite||The debut of Kryptonite in Superman #61 originally has Kryptonite as being red in colour; though it did not possess the same abilities as red Kryptonite does now.
Pre-Crisis red Kryptonite was created from a "flock" of green Kryptonite which passed through a (red-hued) "strange cosmic cloud," some of which arrived on Earth. In this continuity, each piece of red Kryptonite causes a different effect on Superman when he comes into contact with it. However, red Kryptonite effects usually last for only 24 hours. Any given piece of red Kryptonite could usually affect Superman only once. Effects included hallucinations, changing form, paralysis and, when combined with green Kryptonite radiation, even the growing of a third eye at the back of Superman's head, which caused him to disguise the true effect by pretending that the Kryptonite caused him to compulsively wear hats at all times.
In post-Crisis continuity, Mister Mxyzptlk creates what he calls red Kryptonite in the "Krisis of the Krimson Kryptonite" story arc but it has no radioactive properties at all; Superman's depowering is all the result of Mxyzptlk's magic until Luthor unknowingly breaks the rules of his agreement with Mxyzptlk. The first appearance of actual red Kryptonite is as a synthetic variant created by Ra's al Ghul, using notes stolen from Batman. This version of the Red Kryptonite causes Superman intense pain, but not to the lethal levels of Green Kryptonite, the red K having been developed by Batman to stop Superman rather than kill him. When exposed to this red kryptonite, Superman's skin becomes transparent, allowing the sun to directly charge his cells without his skin to act as a filter, resulting in his powers being supercharged to a point where he can hear a grasshopper's heartbeat from the Watchtower on the Moon, requiring him to concentrate just to use his abilities on their normal level. In The Brave and the Bold series, the cloud was drawn to Earth by the deranged alchemist Megistus to shield humanity against the effects of the Final Crisis by warping it into something totally different[volume & issue needed]; the villain Doctor Alchemy also proved capable of transmuting the Fortress of Solitude in its entirety into red Kryptonite using his philosopher's stone[volume & issue needed].
In Lois & Clark: The New Adventures of Superman, red Kryptonite again has varying effects. Initially it causes Superman to become apathetic. It was hypothesized that, given enough exposure to red Kryptonite, Clark's condition would become permanent. However, after talking to a psychiatrist, Clark is able to resist the effects of the red Kryptonite, and he picks up the rock and throws it out of a window. Its later appearances included a red Kryptonite laser which caused Superman's powers to transfer to Lois, and exposure causing Superman to lose fine control of his powers.
On the TV series Smallville, red Kryptonite has a drug-like effect, causing severe changes in Clark Kent's personality. Clark first encounters this effect when he puts on his Smallville High class ring which has a stone of red Kryptonite rather than a ruby. Under its influence, Clark loses his inhibitions, becoming unpredictable and acting purely on erotic and selfish emotions. Once he ran away to Metropolis and became a criminal who broke into automated-teller machines to impress girls with expensive toys such as sports cars. He also stole his father's credit card to buy large screen TVs and high-end audio equipment. Smallville red Kryptonite requires close contact with skin to be effective, such as being worn in a ring or necklace.
In Krypto the Superdog, effects on Krypto include temporary amnesia, loss of all his super-canine powers, causing Krypto's tail to detach from his body and come to life, turning into a fish, and body-swapping.
In Batman: The Brave and the Bold, Batman describes the effect of red Kryptonite as being similar to the pre-Crisis variety, affecting Superman differently every time. In the episode, it is shown in that instance to affect Superman in much the same way it does in Smallville. Superman begins to engage in petty antics, such as sticking a young girl's cat in a tree and humiliating Lois by going on a date with Lana Lang while right in front of her. He also develops megalomaniacal tendencies, which result in him attempting take over Metropolis and declare himself the city's "king". It is discovered by Batman that the effects of red Kryptonite eventually wear off 24 hours after the initial exposure.
|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 (vol. 1) #175 and plays a key role in the 1982 limited series "The Phantom Zone," as well as 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 (vol. 2) #22. In the Legion of Super-Heroes (vol. 2) #293, during "The Great Darkness Saga", it is shown that Element Lad can transmute matter into gold Kryptonite. In Superfriends: The Legendary Super Powers Show, Darkseid buys a quantity of gold Kryptonite in an auction, but thanks to the Superfriends, he accidentally uses it on Batman, and Firestorm transmutes it into a bowling ball before he can try again.
In the Season 10 Smallville episode "Luthor", an alternate-universe Clark bears a scar "L" on his wrist to Tess Mercer. The explanation given is a passing comment, "There's no take-backs with gold K". Gold Kryptonite is further alluded in future episodes. A desperate Jonathan Kent from Earth-2 sought to buy his farm back using it, but it was worthless. A chunk of Gold K is later discovered by a possessed Oliver Queen, and is later presented as a "wedding ring" by the Unholy Trinity (Godfrey, Granny and Desaad) for him to strip Clark of his powers permanently. Chloe Sullivan later notices this and stops it, but a fight happens between Oliver and Clark. Clark talks some sense into him and he crushes the ring, releasing his hold from Darkseid.
|Blue Kryptonite||Blue Kryptonite is the Bizarro analogue to green Kryptonite. Using Bizarro logic, this, in general, hurts Bizarros while having beneficial effects on ordinary Kryptonians.
Pre-Crisis, blue Kryptonite is the result of using Professor Potter's "duplicator ray" on some green Kryptonite. Here, blue Kryptonite affects Bizarros like green Kryptonite affects Kryptonians. Blue Kryptonite radiation is not blocked by normal lead, but by imperfectly duplicated lead. Bizarro World had animated blue-Kryptonite golems underground that surfaced and attacked the superpowered Bizarros while the delighted non-powered Bizarros cheered them on.[volume & issue needed] In the Super Friends episode "Terror from the Phantom Zone," blue Kryptonite heals Superman from the effects of red Kryptonite. Post-Crisis, its origin is unknown. Here, blue Kryptonite makes Bizarros become polite, goodhearted, coherent, and intelligent.
K-Man Blue, a being made of blue Kryptonite, is introduced as part of the Anti-Superman Army in The New 52 run of Action Comics. He appears alongside K-Man Green and Red, two others with the powers of their respective forms of Kryptonite. K-Man Red tells Superman that Blue Kryptonite is the worst of all because it "kills your spirit".
In the television series Smallville, blue Kryptonite suppresses Kryptonians' powers and removes their sensitivity to green Kryptonite, essentially turning them human for as long as they are exposed to it. Blue Kryptonite was first introduced as a Victory Ring given to Clark by a replicant of his mother Lara in "Blue". Also in Smallville, Bizarro's powers were increased exponentially by blue Kryptonite (this version of Bizarro being an 'inverted' Clark, weakened by sunlight and strengthened by green Kryptonite) which overloaded his body with power and killed him, much like "a light bulb being powered by a nuclear reactor," in the episode "Persona".
In episode 7 of season 9, titled "Kandor", Jor-El is shown using blue Kryptonite to remove the powers bestowed by Earth's yellow sun upon the Kandorian soldiers led by Zod as he prepares an orb which will carry to Earth the DNA clones of several of the Kryptonian capital's finest soldiers, treating the samples with blue kryptonite to ensure that the clones couldn't conquer Earth using their powers.
In the season 9 finale, titled "Salvation", blue Kryptonite is used in the form of a dagger by Zod to rid himself of his powers, thus sparing him the trip to whatever planet the Kandorians were going to after Clark used the Book of Rao to save Earth from the coming war. A fight between Clark and Zod ensued whereupon Clark sacrificed himself: he allowed the dagger to be plunged into his gut and then fell from a rooftop, sending Zod to the planet and leaving Clark on Earth. The now powerless Clark is seen falling to the streets below. The aftermath of these events was not expected to be seen till the first episode of season 10, as it was a cliff-hanger.
In Episode 6 of Season 10, titled "Harvest", Blue Kryptonite is shown to purify water to the extent that humans drinking it do not become sick from common viruses. It also can be linked to improving crop production. Clark is unable to use his powers around people who have been drinking water contaminated by the blue Kryptonite.
|Black Kryptonite||Black Kryptonite first appeared in the Smallville television series, in the fourth season premiere episode "Crusade," as Kryptonite with the ability to split the personality of Kryptonians along with reversing this process. It later appears in the fourth season episode "Onyx," where it is revealed it can also affect humans and vegetations as well in the same way as Kryptonians. In the series, black Kryptonite can be created by super-heating green Kryptonite. Later in the season eight finale "Doomsday," Clark acquires, and then Chloe uses, black Kryptonite to successfully separate the Kryptonian monster Doomsday from its human alter ego Davis Bloome in order to defeat Doomsday without having to kill Davis.
It later made its first appearance in a DC comic in September 2005's Supergirl #2, where it apparently possessed the ability to split a person or a person's personality into two separate entities. In Supergirl #3, Luthor used black Kryptonite on Supergirl, which caused her to split into two separate people, one wearing Supergirl's traditional costume, and another wearing a black-and-white version. Luthor claimed that he was given the black Kryptonite by Darkseid, which had similar effects on Superman, creating an evil Superman. In All-Star Superman, which takes place outside of DC Universe continuity, black Kryptonite makes Superman evil. In an issue of Superman/Batman, while remembering the abilities of the different forms of Kryptonite, he exclaimed "Black and I'm robbed of my sanity", accompanied by a broken wedding picture of Lois and Clark covered in blood. This suggests that in some form or another black Kryptonite can negatively impact Superman's morals and behavior, twisting his normal state of mind.
|White Kryptonite||Kills all plant life, whether Kryptonian or not. Induces decay immediately upon exposure, with a range of about 25 yards. The most prominent use of this variety in the comics was to destroy Virus X.
In the TV show Superboy (renamed "The Adventures of Superboy" in its third season) White Kryptonite is referred to as "Bizarro Kryptonite". It had no effect on Superboy but when used on Bizarro Superboy, it made him become stable, and calmed his mind.
|Silver Kryptonite||In Smallville, while visiting Lana Lang in Metropolis, Clark opens a package addressed to Lana apparently sent by Lex Luthor and is wounded and infected by a splinter of silver "Kryptonite". It causes Clark to have paranoid delusions, and he sees Chloe, Jonathan, Martha, Lana, and Lex plotting against him. He defends himself against his "enemies," jeopardizing the lives of his dearest friends and family. Eventually, help comes from a most unlikely source: Milton Fine. Silver Kryptonite is not a real piece of Krypton, it is a rock from earth infected with a sliver of the metallic morphing body of Brainiac. Brainiac or Milton Fine as he was called at this point created Silver Kryptonite in order to help Clark rid himself of it, thus gaining his trust.
In a storyline in the ongoing series Superman/Batman entitled "The Search for Kryptonite," a piece of silver Kryptonite causes Superman to act like a hyperactive child and for his vision to depict everyone around him as strange, chibi versions of themselves drawn in a very cartoony style. The only way to restore him to normal was to use another piece of the material located in a volcanic region and expose him to it. The two shards of silver Kryptonite are currently located in the Batcave.
|Orange Kryptonite||Gives super-animalian powers, stronger than Krypto's, for precisely 24 hours to any animal that touches it; ineffective on humans. May be repeated immediately following the 24 hours for quasi-continuous super-animalian powers. First introduced in Krypto Comics #4, Feb. 2007.|
|Jewel Kryptonite||Jewel Kryptonite amplifies the psychic powers of Phantom Zone residents, allowing them to project illusions into the "real world" or perform mind control. It was made from what was left of a mountain range on Krypton called the Jewel Mountains.|
|Anti-Kryptonite||Has no effect on superpowered Kryptonians, but has the same effects as green Kryptonite on non-superpowered Kryptonians. This version of Kryptonite is what killed most of the residents of Argo City in the pre-Crisis comics. Post-Crisis, it is the power source of Ultraman, Superman's evil counterpart who lives in an alternate antimatter universe. Anti-Kryptonite was also used by Green Lantern Hal Jordan while rescuing a member of the Green Lantern Corps (Guy Gardner) from the Phantom Zone by causing pain to General Zod, Kru-El, and Faora, since regular Kryptonite has no effect on individuals in the Phantom Zone.|
|X-Kryptonite||Not to be confused with Kryptonite-X, it was created accidentally (and unknowingly) by pre-Crisis Supergirl during experimentation with green Kryptonite, in an unsuccessful attempt to find an antidote. The "unique combination of chemicals" used by Supergirl created "something new under the sun," whose radiation (and odor) can imbue Earth-based life-forms with temporary superpowers. It is primarily known as the source of Supergirl's pet cat, Streaky's superpowers. Originally it had additional effect on Kryptonians (although the latent Kryptonite radiation is still harmful to them) but this was changed in 1974 to having the same effects as green Kryptonite.|
|Slow Kryptonite||A modified variety of green Kryptonite produced by supervillain Metallo that affects humans in a manner similar to normal green Kryptonite on Kryptonians, appearing in The Brave and the Bold #175.|
|Magno-Kryptonite||Artificially created by the villain Nero, "magno-Kryptonite" is magnetically attracted to all substances originally from Krypton, with such incredible force that not even the strength of Superman or Bizarro can escape it according to Superman's Pal Jimmy Olsen #92.|
|Bizarro Red Kryptonite||Affects humans the same way red Kryptonite affects Kryptonians. Appeared in Superman's Pal, Jimmy Olsen #80.|
|Kryptonite-X or Kryptisium||Not to be confused with X-Kryptonite, Kryptonite-X is a form of filtered/purified Kryptonite. Professor Hamilton used the term "Kryptonite-X" (The Adventures of Superman #511, April 1994, page 13) to describe the substance that restored Superman's powers after a confrontation with the villain known as the Cyborg Superman in Engine City (Superman v2, #82, part of the "Return of Superman" storyline). This substance was created when the Cyborg used a huge chunk of green Kryptonite in an attempt to kill the weak, powerless, recovering Superman. The Eradicator, who had fashioned a faux-Kryptonian body, jumped in front of Superman before the release of the Kryptonite energy could kill him. Despite the Eradicator's efforts, the Kryptonite energy hit Superman, but instead of killing him, it transferred all of the characteristic Kryptonian powers from the Eradicator to Superman, as well as saturating Superman's body with a purified/filtered form of Kryptonite.|
|Pink Kryptonite||From Supergirl (vol. 4) #79, an alternate Earth-One timeline in a 2003 Supergirl storyline by Peter David. It affected the Superman of this reality by giving him gay tendencies. One of the results of this is Superman giving flattering compliments to Jimmy Olsen about his wardrobe and decorative sense. It spoofs the more "innocent times" of the Silver Age; Lois Lane is depicted in this story as not understanding what has gotten into Superman.|
|Gemstone Kryptonite||On Smallville, this new Kryptonite gives Clark the ability to make others want to fulfill his wishes. Simple conversations with a gemstone infected person influence others to act out of character to do whatever they perceive was asked of them. Likewise, the infected person could also influence himself. The influenced person could not then be counter influenced by the infected person asked. Green Kryptonite removes the infection. This only appeared in the Season 9 episode "Persuasion".|
|Hybrid-K||In Lois and Clark, Hybrid-K has the same effect on humans that Green Kryptonite has on Kryptonians. Created by a former S.T.A.R. Labs scientist Jefferson Cole, it was described as pure death, able to kill thousands without destroying any surrounding structures, making it 'environmentally friendly.' After framing Lois for murder, Cole stole the Hybrid-K from S.T.A.R. Labs, hoping to slaughter the people of Metropolis and have the carnage blamed on Superman and Dr. Klein in revenge for having him fired from S.T.A.R. Labs and imprisoned. He seeded rain clouds with the Hybrid-K to create a toxic storm. However, the chemical composition differed enough from normal Kryptonite as to have no effect on Kryptonians, thus, unaffected by the rain, Superman was able to whirlwind the Hybrid-K out of Metropolis. This only appeared in the Season 4 episode "Dead Lois Walking".|
|Periwinkle Kryptonite||In Superman Family Adventures, Periwinkle Kryptonite makes Superman "fabulous," causing him to dance with Lois and imagine he sees disco balls and pink walls. Lois then lays a chunk of Periwinkle Kryptonite on Clark's desk and the two dance, proving that Lois knows Clark's secret identity.|
Simulated Kryptonite 
- Green Lantern Corps power rings can be used to emit simulated green Kryptonite radiation. Kyle Rayner did so in Man of Tomorrow #19 (1998). The duplicate "Hal Jordan" Green Lantern form of N'Gon also created Power Ring-based green Kryptonite in DC Comics Presents #26, and Superman used the yellow of his cape's "S" design to block the effect. Green Lantern Hal Jordan also uses his ring to make Kryptonite effects in numerous Justice League of America stories in order to cause Superman to be temporarily affected by things his invulnerability would otherwise prevent. This radiation is apparently just as powerful and painful to Superman and other Kryptonians as the genuine rays, but it can be blocked by interposing anything yellow between the Green Lantern's green Kryptonite and the Kryptonian (however, this may no longer be an option due to the recent development of yellow no longer being an automatic weakness of power rings). Breaking the ring-bearer's concentration will also dispel the effect.
- Synthetic Kryptonite (usually the green or, occasionally, red variety) has been successfully produced by Lex Luthor, Batman, and Ra's al Ghul in the comics. It has proven to be less powerful than genuine Kryptonite, which proves to be extremely difficult to create, and to have a short half-life that renders it useless after a short period of time. In the Elseworlds story The Dark Knight Returns, Green Arrow wounds Superman with a synthetic Kryptonite arrow, allowing Batman to defeat him. Bruce Wayne notes it was very expensive to develop, taking years to properly synthesize. Superman III featured synthetic Kryptonite with substituted ingredients, that altered Superman's personality and eventually caused him to split into two beings with differing personalities.
- Hybrid Kryptonite was seen on Lois and Clark in Season 4 Episode 07 (Dead Lois Walking). This Kryptonite was made by a villain who used to work with Dr. Klein at S.T.A.R. Labs until he was fired. Hybrid Kryptonite seemed to have the effects of green Kryptonite on humans, but had no effect on Kryptonians.
- Magic: Individuals adept at the use of magic may be able to create Kryptonite, such as Mr. Mxyzptlk did in the "Krisis of the Krimson Kryptonite" storyline (though his version of Red Kryptonite differed from the traditional version in its workings, temporarily eliminating Superman's powers). Jimmy Olsen, when changed into a genie in Superman's Pal, Jimmy Olsen #42 (January 1960), was ordered by his master, Abdul, to turn himself into living Kryptonite; Jimmy chose green Kryptonite.
- On one occasion, Lex Luthor combined the element-duplicating substance that composes the robots known as the Metal Men into a single robot that imperfectly duplicated the properties of green Kryptonite. While its presence caused Superman severe pain, it was not severe enough to completely incapacitate him, and did not affect his powers at all; thus, Superman was able to focus past the pain and defeat the robot.
- Telepathy: During the first confrontation with the White Martians, their leader, Protex, was able to incapacitate Superman by using his telepathy to convince Superman that he was in the presence of green Kryptonite, but Superman was able to resist this influence after he realized what was happening. Gorilla Grodd also once used this trick on Superman, his influence being so strong that the Man of Steel still felt the effects of Kryptonite even after Grodd mockingly told him the truth.
- Radiation: In the film Superman III, the computer Webster built was able to analyze Superman and find his weakness, and emitted a beam of radiation that simulates that of green Kryptonite. It was stopped only when Gus Gorman pulled the plug.
- Crystals: The film Superman Returns has Lex Luthor combining Kryptonian crystal technology with green Kryptonite, causing the rapidly growing crystals to take on the properties of Kryptonite and making the entire landmass of "New Krypton" deadly to Superman, although far less so than pure Kryptonite.
In the comics and other media, some varieties of Kryptonite that turned out to be hoaxes:
- Silver Kryptonite: Featured in Superman's Pal, Jimmy Olsen #70, silver Kryptonite is a hoax revolving around the silver anniversary (25th) of Superman's career. Silver Kryptonite in another form is a part of the Smallville TV series (see Smallville below), and was shown in the comics continuity in Superman/Batman #46.
- Yellow Kryptonite: This one was used in a hoax masterminded by Lex Luthor Action Comics #277.
- Blood Kryptonite: In 52, the Cult of Conner - a religious sect dedicated to resurrecting Superboy, employed "blood Kryptonite" in a preliminary ritual to resurrect Sue Dibny. While physically resembling red Kryptonite, the "blood" variant drains a portion of life force from present attendees, intended to direct this energy towards an effigy of the deceased as part of a Kryptonian resurrection ceremony. It is later revealed that this was a manipulation of Felix Faust and the rock was either regular red Kryptonite or not Kryptonite at all.
- Kryptonite Plus: 30 or so non-glowing, varicolored, banded rocks invading unnamed Super-aliens had left on Earth's moon and then said were Kryptonite plus or maybe a form of ultra-Kryptonite. They are really Tikron Stones, artificially made by the alien's ancestors. From Superman's Pal, Jimmy Olsen #126 (January 1970).
- Purple Spotted Kryptonite: Mentioned in Streaky's fictional story in the animated cartoon Krypto the Superdog. This phony Kryptonite made Krypto chase his tail.
- Fake Kryptonite: Seen in an episode of the Superboy 1988 TV series, Superboy's friends are selling crystals which are labeled as "fake Kryptonite" to raise money for charity. These crystals are clearly false and the vendors make no dispute about it. However, they use humorous references such as "Buy one and have nothing to fear; even Superboy will run away from you!".
Scientific basis 
||This section needs additional citations for verification. (July 2012)|
Under standard chemical naming procedures, the -ite suffix of Kryptonite would denote an oxyanion of the element krypton. However, krypton is a noble gas that forms compounds only with great difficulty, and such an oxyanion is not known. Nevertheless, the University of Leicester presented the Geological Society with krypton difluoride to commemorate the 70th anniversary of Superman.
In virtually all versions of the Superman mythos, Kryptonite is described as having formed through a process of nuclear fusion attendant to the explosion which destroyed the planet Krypton. Some accounts describe the fusion process as a result of the planet-destroying explosion, others as the cause of it, but all agree that the majority of the debris of the planet was converted into Kryptonite and propelled into interstellar space by the force of the explosion, with some ultimately reaching Earth and becoming a threat to Superman—and other Kryptonians. In Krypton's former location there is a cloud of gas-form Kryptonite that is lethal to all beings, Kryptonian or not.
The term Kryptonite instead implies a meteorite from the planet Krypton, as in the Lois & Clark: The New Adventures of Superman episode "The Green, Green Glow of Home," where it is given as "periodic element 126", which in reality corresponds to unbihexium/eka-plutonium, the most stable of the elements in the so-called island of stability. Superman: The Man of Steel Sourcebook (1992), while non-canon, concurs, referring to Kryptonite as "the common ore of the super-actinide Kryptonium, an unusually stable transuranic element, whose atomic number is believed to be 126". Kryptonium is given a radioactive half-life of 250,000 years.
In Superman: The Movie, Lex Luthor describes Superman's enhanced Kryptonian physiology as being vulnerable to Kryptonite's particular radioactive "signature". More recently, some issues of Superman indicate the mechanism by which green Kryptonite may hurt Superman. Superman's cells absorb electromagnetic radiation from stars (like Earth's sun). Kryptonite's radioactivity interferes with this semi-photosynthetic process, driving the energy out of his cells in a painful fashion.
Some versions of the adverse effects of Kryptonite describe the radiation as affecting the blood chemistry of the victim, causing accelerated effects similar to sickle cell anemia[original research?] in terrestrial humans, and also causing the skin of the victim to turn green as exposure time increases.
Long-term exposure to Kryptonite is said to have the same effects on terrestrial human beings as exposure to other radioactive materials; an extended storyline in the comics around 1990 involved Lex Luthor developing cancer from the Kryptonite ring he kept on his finger.
In other media 
As noted above, Kryptonite was originally created for the 1940s Superman radio series. Kryptonite has appeared in various forms in the various Superman media spinoffs, however.
Kryptonite was used in both 15 part movie serials produced by Columbia Pictures. In Superman (1948), the Spider Lady (Carol Forman) and her gang use Kryptonite against the Man of Steel (Kirk Alyn). In Atom Man vs. Superman (1950), Luthor (Lyle Talbot) creates a synthetic form of Kryptonite to use against Superman.
Superman: The Movie 
In Superman: The Movie, Lex Luthor (Gene Hackman) and his cronies Eve Teschmacher and Otis (portrayed by Valerie Perrine and Ned Beatty, respectively) track a large chunk to Addis Ababa, Ethiopia, where they steal it from a museum under the cover of night. In this film's usage, the term "Kryptonite" seems to mean simply a "Kryptonian meteorite". After co-opting and launching two missiles for opposite ends of the United States, Luthor places the Kryptonite on a chain around Superman's (Christopher Reeve) neck and drops him into a swimming pool. When Teschmacher learns that one of the missiles is headed for Hackensack, New Jersey (where her mother lives), she rescues Superman from drowning and removes the Kryptonite, after which his strength and powers quickly return.
Superman III 
In Superman III, billionaire Ross Webster (Robert Vaughn) orders the creation of synthetic Kryptonite after remembering a Daily Planet story about the last original chunk disappearing years earlier after falling to Earth. After scanning the coordinates of Krypton's former location via satellite, computer programmer Gus Gorman (Richard Pryor) determines that Kryptonite is "an intense heat fusion" of: 15.08% plutonium, 18.06% tantalum, 27.71% xenon, 24.02% promethium, 10.62% dialium (which is a plant genus, not an element), 3.94% mercury, with the last 0.57% being an unknown element not found on the periodic table. The substitution of tar (which Gorman used after glancing at a pack of cigarettes) for the crucial, but unknown, component resulted in the synthetic Kryptonite—like black Kryptonite in the comics—turning Superman evil and eventually splitting him into two people. Retaining Superman's remaining good qualities, Clark Kent defeats the dark Superman, who vanishes. Later in the film, Gorman's creation, the Ultimate Computer, severely weakens Superman with a Kryptonite ray before Gorman has a change of heart and attacks his own machine.
Superman Returns 
In Superman Returns, Lex Luthor (now portrayed by Kevin Spacey) enters the Metropolis Museum of Natural History and steals the Addis Ababa L9 Pallasite Meteorite, which was discovered at the Kebe Mine in Addis Ababa, Ethiopia. It is described in the exhibit display as “sodium lithium boron silicate hydroxide with fluorine”. According to the exhibit display, the meteorite was discovered in 1978 — the year that Superman: The Movie was released. Incidentally, in 2007, a white and harmless mineral with the above chemical formula (except without fluorine) was discovered by Rio Tinto Group researchers in a mine in Serbia called Jadarite.
Luthor uses the meteorite in his quest to create a new Kryptonite landmass (which is referred to in the novelization as "New Krypton"). In addition, he uses a shard leftover from processing it to create a Kryptonite shiv, which he uses to stab Superman (portrayed by Brandon Routh). After Lois removes the shiv from Superman's back, he flies to the Sun and lifts the continent into space.
Justice League: Crisis on Two Earths 
In the animated direct to video movie, Justice League: Crisis on Two Earths, Blue Kryptonite makes a brief appearance. As the heroic Lex Luthor of the parallel universe battles his arch enemy Ultraman (that universe's evil Superman), he is beaten but, gains the upper hand by revealing, and weakening Ultraman with a piece of blue Kryptonite, the only thing he is vulnerable to (mirroring Superman's weakness to the green variety). When confronted by it Ultraman is severely weakened, and claims to have destroyed all the pieces of it left; Lex admits that Ultraman did, but that he himself has been to other universes and gotten more.
Justice League: Doom 
Green Kryptonite appears in the direct to video movie, Justice League: Doom. In the film, Metallo nearly kills Superman by shooting him the chest with a bullet made of Green Kryptonite, sending him falling from the roof of the Daily Planet and onto the pavement below. Superman's Kryptonian skin prevents the paramedics at the scene from removing the bullet, but he is ultimately saved after Cyborg uses a makeshift Kryptonite laser to cut an incision in the hero's chest, allowing Martian Manhunter to remove the Kryptonite before it kills him.
Man of Steel 
Adventures of Superman 
Kryptonite was used in several Adventures of Superman episodes. The specific color is not definite, given that it is never mentioned and that the series was initially in black-and-white, but from its effects, it is presumably green Kryptonite in each case:
- In "Panic in the Sky", Superman’s attempt to shift a meteor hurtling toward Earth leaves him with amnesia. Although the scientists in the episode only say the meteor consist of "unknown elements", a fragment of this meteor is later used in "The Deadly Rock", referred to at that time as Kryptonite.
- In "The Defeat of Superman", an overacting scientist working for a crime boss synthesizes Kryptonite after working out the formula from a tiny fragment found in a meteorite. As Superman lies dying from the metal's effects, Lois and Jimmy rescue him for once, sealing the block of Kryptonite in a lead pipe, and Superman recovers. He then flings the pipe through the sky and into the sea with a super-throw. The escaping criminals, startled by the rocketing pipe, veer off the road and plummet to their deaths, keeping this dangerous secret "safe" in the hands of Superman's two friends.
- In "Superman Week", Jimmy, under the influence of truth serum, reveals the secret to some criminals. Superman stages an elaborate ruse in which he pretends to have retrieved the lead-encased metal from the ocean, and uses it to lead a wanted criminal into a trap. This ruse also presumably proves that Superman is not vulnerable to it, thus staving off criminals' thoughts of using it. for a while.
- In "The Deadly Rock", another eccentric scientist finds a meteorite that happens to be from Krypton, and a crime boss tries to use it to destroy Superman, who instead destroys it through the unlikely method of burning it with a flame-thrower. "The Deadly Rock" is also one of the first stories to depict Kryptonite affecting a human. Gary Allen, a pilot, is said to have been exposed to the resulting meteor shower during the events of "Panic in the Sky" and as a result gains invulnerability in the presence of Kryptonite but loses consciousness as well.
- In "The Magic Secret", yet another eccentric scientist teams with a criminal, this time tricking Superman into descending a narrow and deep well to rescue Lois and Jimmy, then proceeding to shower the Man of Steel with Kryptonite particles.
- In "The Gentle Monster", Professor Pepperwinkle—a very eccentric but good-natured scientist—constructs a superpowered robot whose strength is derived from a chunk of the metal that the scientist has found, not knowing the danger it poses to Superman.
- In the series' final episode, "All That Glitters", Jimmy is struck on the head by a falling sandbag and rendered unconscious. During a very lifelike dream, Jimmy imagines that Professor Pepperwinkle has discovered that Kryptonite is actually made of two components: Kryptonite-positive and Kryptonite-negative. Superman's body is said to be charged with K-positive—thus granting him his powers—while K-negative is said to neutralize the K-positive charge, destroying his powers. Pepperwinkle develops a means of isolating and purifying the K-positive, and of reducing it to pill form. Before he awakens from the dream, Jimmy imagines that he and Lois each develop powers like those of Superman after swallowing a K-positive pill.
The Adventures of Superboy 
Kryptonite made frequent appearances in the syndicated "Superboy" TV series, most of it green. It first appeared in the first season episode "Kryptonite Kills" in which Professor Peterson retrieved it from Addis Adaba believing it to be a harmless meteorite and brought it to his gemology class at Shuster University. Superboy in his guise as Clark Kent (played by John Haymes Newton in Season 1, Gerard Christopher in Seasons 2-4), a student in Peterson's science class, collapsed from the radiation and felt its effects for the first time. While attention was focused on Clark, Lex Luthor (played by Scott James Wells), another student in the class, swiped a small piece of the rock for himself, using it as a power source and fashioning it as a necklace for his girlfriend. Superboy later threw most of the Kryptonite into space, except for Lex's piece, which was washed into the sewer. That piece was later discovered by a scientist who used it as a power source for Metallo (Roger Corben) in the second season episode of the same name.
Green Kryptonite made several more appearances throughout the series, used primarily by Lex Luthor (played in these later episodes by Sherman Howard) and Metallo (subsequently portrayed by Michael Callan). In the third season episode "Bride of Bizarro", Luthor sent Bizarro to a military research base to steal a large amount of Kryptonite, which Luthor was seen using on Superboy in later episodes. In the fourth season episode "Kryptonite Kid", a young man named Mike Walker (played by Jay Underwood) working at the same military research base was caught in a Kryptonite explosion while working to find a cure which would make Superboy immune to the radiation. The Kryptonite entered his bloodstream and turned his skin green and he became "living, breathing Kryptonite" able to fire Kryptonite radiation from his hands. However, Superboy foils it with a lead tarp and says that with medical treatment the Kryptonite will be cleansed from Walker's body. In "Obituary for a Super-Hero", Luthor used a Kryptonite bomb planted on a yacht to attempt to kill Superboy.
Red Kryptonite made an appearance in the second season episode "Super Menace". This version of Red K was created at a military research base where scientists were working to neutralize Kryptonite's effect on Superboy while still retaining its radioactive properties so it could be used as a power source. Their experiments turned the Kryptonite red, making it useless as a power source and altering its effect on Superboy. This red Kryptonite turned Superboy evil, much like red Kryptonite would later do in the "Smallville" TV Series, except only a single exposure to it was required, rather than constant exposure. After Superboy wreaked havoc with Metallo, Lana Lang (played by Stacy Haiduk) tricked Superboy into being exposed to another chunk of red Kryptonite which reversed the effects of the first.
The "Superboy" series also introduced a form of white Kryptonite, created by Professor Peterson's duplicating ray in an attempt to create a form of Kryptonite that would kill the molecularly unstable Bizarro. It had an opposite effect, actually stabilizing, curing, and preventing him from eventually exploding as previous Bizarro duplicates had. White Kryptonite made only one appearance in the series in the episode "The Battle With Bizarro". It is referred to again in "The Bride of Bizarro" but it is not seen.
Lois and Clark: The New Adventures of Superman 
Kryptonite was used throughout the 1990s television series Lois & Clark: The New Adventures of Superman.
- In "The Green, Green Glow of Home" the first piece was unearthed on the Smallville farm of Kent family friend Wayne Irig. He sent a sample of the rock to a local university. This came to the attention of Jason Trask. Trask headed Bureau 39, a secret government organization that investigated perceived alien threats. Trask had the paranoid belief that Superman was the first agent of an alien invasion. Understanding that the radioactive meteorite came from Krypton, he attempted to use the rock to kill Superman. Subsequently the main fragment of the meteorite was destroyed and Trask was killed by the local sheriff. Consequently only Clark Kent and his parents knew of its true existence. Clark and his partner Lois Lane reported on the incident in The Daily Planet and described Trask's delusions of a fabled rock that could kill Superman. Ironically, in this article, it was Clark Kent himself who first named it "Kryptonite".
- As shown in "Barbarians at the Planet" and "The House of Luthor", the story of Kryptonite intrigued Superman's archenemy Lex Luthor. He used the many resources at his disposal to track down and confirm the existence of the original sample that Irig had sent to be studied. Luthor ground down part of this Kryptonite and used it to coat the bars of a cage to entrap the Man of Steel. It is mentioned earlier that Lex's people were studying the "K-field", and probably found a way to enhance the natural radiation of Kryptonite, since the bars had relatively minor effect on Superman until somehow activated. After Superman's escape from this Kryptonite prison and Luthor's apparent death, the legend of Kryptonite continued to grow. In the first season, Kryptonite was portrayed as having a residual effect on Clark, leaving him powerless for a while (which prevented him from saving the falling Lex Luthor), but subsequently Clark was portrayed as recovering instantly after Kryptonite exposure.
- Many criminals and former Lexcorp employees sought to acquire Luthor's Kryptonite. In fact most of the Kryptonite to be featured on the series originated from that first chunk found by Wayne Irig. During the 3rd season a new second piece was discovered, which Superman turned over to S.T.A.R. Labs for testing. This was the source of most of the Kryptonite featured for the remainder of the series. It was attempted by S.T.A.R. Labs to make Superman immune to Kryptonite by controlled exposure to the radiation. The exact amount of success is unknown, but it is known that Kryptonite never affected Superman as strongly as the very first time, when a short exposure caused a temporary complete loss of powers. This sample was later stolen at the beginning of the fourth season by the military, ground down to lace a gas grenade in an attempt to kill an invading force of Kryptonians (and Superman as collateral damage.)
- On Lois and Clark, green Kryptonite was delivered in a variety of ingenious ways. A bullet was fashioned from pure Kryptonite in one episode, and in another, a wicked woman tried to bring about Superman's demise by kissing him after coating her lips with a Kryptonite-contaminated lipstick. In the episode "Metallo", scientist Emmett Vale, who studied Luthor's Kryptonite while working at Lexlabs, used a piece to power the cyborg he created from fatally wounded criminal John Corben.
- Red Kryptonite was also featured in the series. In one episode, it made Superman apathetic; in another, it transferred his powers to Lois Lane after being focused through a laser beam. In yet another, it made him lose fine control of his powers, causing him to do things such as accidentally fly through the sidewalk when landing.
- A renegade S.T.A.R. Labs scientist created a "hybrid Kryptonite," which was supposed to be just as deadly to humans as to Kryptonians. When used however, it was discovered that while the hybrid Kryptonite made humans sick, it had no effect on Superman.
In the 2000s and 2010s television series Smallville, a large quantity of green Kryptonite falls to Earth (in the town of Smallville, Kansas) as a meteor shower in 1989—arriving at the same time as the spaceship containing the infant Kal-El. The size and quantity of the rocks are large enough to hide the spaceship from the radar being employed by various nations in the late 1980s. Additionally, the meteor shower is directly responsible for the loss of Lex Luthor's hair (caused by exposure to Kryptonite radiation) and the death of Lana Lang's parents (who were struck by a Kryptonite meteor). The element is originally referred to as "meteor rock", rather than "Kryptonite," even by Clark Kent. In the season two episode "Rosetta", Clark learns the name of his home planet for the first time, and the term "Kryptonite" eventually comes into use by those characters who know Clark's secret.
On the show, not only is green Kryptonite harmful to Clark Kent, but it can produce bizarre changes in humans, animals, and plants, typically turning them into powerful metahuman menaces, commonly known by the inhabitants of Smallville as "Meteor Freaks," that Clark must oppose. These changes seem to be linked to the circumstances under which the subject was exposed to Kryptonite, the subject's emotional state, their personality, and even their profession (similar to how gamma radiation affects people in the Marvel Comics universe). Groups of people have been shown to acquire the same powers or similarly related powers from Kryptonite by exposing themselves to it in the same manner. One hitch to these powers has been that they, for the most part, have no effect on Clark, provided they are generally used offensively and are powers that have manifested due to a single large exposure to Kryptonite (either from the meteor showers or from some one-time clamity that results in instantly altering the person). Clark reacts to people who use Kryptonite infused items to gain temporary powers (e.g. laced tattoo ink; laced steroids; laced paint) in the same manner as he reacts to Kryptonite as the infused item still radiates (albeit, not as potently), passive meteor powers often still work on Clark (in Obsession, Alicia is able to teleport Clark), and, in few cases, the 'freak-of-the-week's' ability has a much more drastic effect on Clark than on humans (In Hourglass, Clark is able to see his future, where, with humans, only Cassandra can see their future and she has to tell them. In the episode Blank, a teen with the ability to erase memories accidentally erases Clark's entire life, whereas, with humans, he is only able to erase a few minutes.)
The harm inflicted on Clark by Kryptonite on Smallville is varied. He cannot be near green Kryptonite without doubling over in nausea and pain, and if he were to hold a fragment of it in his hand, it would burn to the touch and the veins in his hand would become exposed and green. However, on other separate occasions, Clark has held (Jinx) and even ingested (Devoted) Kryptonite (albeit in diluted form) and been merely weakened. When a vial of Clark's blood was held up to Kryptonite to verify its authenticity, the blood began to boil. Higher refined Kryptonite seems to also have a stronger effect and larger effect radius.
In the season eight episode "Power", Lana Lang (in an effort to gain the power necessary to fight crime alongside Clark) acquires an experimental skin-replacing "suit" known as "Project Prometheus". The suit was designed for Lex Luthor and grants Lana superhuman abilities. In season eight's "Requiem", she learns that the suit has the added ability to absorb and emit Kryptonite radiation. In a cruel setup by Lex, Lana is forced to absorb a large amount of Kryptonite radiation, which is being used as an explosive capable of leveling most of Metropolis. As a result, Lana is forced to leave Smallville and Clark forever, or risk killing Clark as she gets too close to him. Lex also fashioned Kryptonite rings with Luthor's family insignia for himself in preparation for his eventual confrontations with Clark. Oliver Queen took one of the rings from Lex after his apparent death, though he does not confirm when confronted by Clark whether he intended it for use as an insurance policy against Clark himself.
Also, it is worth noting that, as a nod to some Superman comics, Clark on rare occasions has displayed some resistance towards Kryptonite. A notable example was when he somehow survived an explosion while imprisoned in a Kryptonite cage in the season ten episode "Patriot". He has also somehow retained some of his powers while under Kryptonite exposure, such as X-ray vision when trapped in the Kryptonite cage and super-breath when he was held captive by Granny Goodness in the season ten episode "Abandoned".
Red Kryptonite has also been shown in Smallville. Its effect on Clark Kent is to rid him of all inhibitions, making him rebellious and potentially dangerous if exposed to it for too long. Also created for the series was black Kryptonite (first appearing in the episode "Crusade"), which is capable of separating certain entities within individual organisms, e.g., splitting a person's good and evil sides.
Black Kryptonite was formed by heating up green Kryptonite. In the series, after Clark's "reprogramming" by Jor-El in the caves, Martha Kent used black Kryptonite to reveal the two psyches of Clark, the militant Kal-El (not to be confused with the rebellious "Kal" alias caused by red Kryptonite), and normal Clark. In a later episode, Lex Luthor was experimenting with a process to heat up green Kryptonite and irradiate seeds, in order to separate the "weak" genes from the "strong" genes in the seeds. The result was hardy but rotten-tasting fruit, implying a yin and yang balance within fruit, as well as within humans. An accident with this process caused Lex to split into a bad Lex and a good Lex who referred to himself as "Alexander". In the eighth season episode "Injustice", Oliver Queen retrieved a supply of black Kryptonite, which Chloe used on Davis in "Doomsday".
Silver Kryptonite made an appearance in the fifth season episode entitled "Splinter'. Like the previous comics incarnation, this silver form was not a true form of the stone. In the episode, Clark pricked his finger on a rock that was black and had silver-metallic clusters, and subsequently became increasingly paranoid, hallucinating that others were conspiring against him. In the episode's final scenes, it was revealed that a splinter of the element entered Clark's bloodstream. It was also shown that silver Kryptonite was created artificially from the liquid metal which forms Brainiac's body.
In the eighth episode of Smallville's 7th Season, entitled "Blue," there was a new form of Kryptonite. It was blue Kryptonite, and it stripped Clark of his powers. This happened when Lara, Clark's mother, gave Clark his father's blue ring to wear, without knowing the effect it would have on him. The ring was impossible to remove until Clark returned to the Fortress of Solitude. As in the comics, blue Kryptonite is fatal to Bizarro. It increases Bizarro's power exponentially so that his body is not able to contain it, causing him to explode.
In season 9 episode 7, titled "Kandor", Clark's father Jor-El, a prominent scientist on Krypton, is tasked by the Kryptonian high counsel to prepare DNA clones of the planet's finest soldiers during the war with Black Zero. Knowing the powers bestowed by Earth's yellow sun, Jor-El uses blue Kryptonite to prevent the clones from having the powers bestowed upon his son, Kal-El (Clark) should they be unleashed from their transport orb on Earth.
In season 9 episode "Persuasion" a new Kryptonite called Gemstone Kryptonite gave Clark the ability to have others want to fulfill his wishes.
In season 10's "Luthor" gold Kryptonite is mentioned by the alternate reality Clark Kent, the evil Clark Luthor/Ultraman. He implies that "gold K" is responsible for a notable scar on his wrist. Gold Kryptonite finally appears in the episode 20, "Prophecy", when Oliver, infected by Darkseid, was digging in a forest and ended up finding a piece of the gold meteor rock. It is later featured as a wedding ring given to Oliver to plant it on Clark, ridding him of his powers, but Oliver overcame Darkseid and crushed the ring.
Animated series 
Super Friends 
The 1970s and 1980s Super Friends animated series featured Kryptonite in various episodes. In the episode "Rest in Peace", Sinestro refers to a form of Kryptonite called "Krypton Steel" as "a harmless form of Kryptonite that only Superman can penetrate". In another episode, "Darkseid's Golden Trap", gold Kryptonite appears, which is stated to have an effective range of 20 ft (6.1 m). Blue Kryptonite also makes an appearance in an episode entitled "Terror From the Phantom Zone"; Superman, aging rapidly from exposure to red Kryptonite, acquires a sample of blue Kryptonite which had been discovered floating in space. Since blue Kryptonite harms Bizarros, Superman reasons that it would help normal Kryptonians, and thus uses it to cure himself. In "Uncle Mxyzptlk", the Wonder Twins find a red, glowing stone and take it to the Hall of Justice. They show it to Superman, who immediately reacts to it. Samurai knocks the red Kryptonite to the floor but the effects of the red Kryptonite cause Superman to decrease in age, becoming a young child. The rest of the Super Friends refer to the kid as 'Super Brat'. In another episode, red Kryptonite is exposed to Superman by Bizarro himself, causing Superman to transform into a gangly, weak klutz. In yet another episode, red Kryptonite causes Superman to grow additional arms and legs. Most of the action takes place at the Fortress of Solitude, where Superman finds some blue Kryptonite hidden away to fight off Bizarro, but unlike the earlier case of curing superman from his artificial old age, this session of blue kriptonite didn't heal superman (But the first case was a huge meteor, and the latter was just a small chunk.)
DC Animated Universe 
In the 1990s series, Superman: The Animated Series, one explanation offered for the science of Kryptonite is that Superman feels the detrimental effects of Kryptonite radiation quicker than normal humans because his body absorbs it more readily, as a result of sharing a common point of origin with the element. The effect is so potent that even a tiny shard is enough to painfully affect Superman at a short distance. This makes it impossible for Superman to even touch the substance, as it would be the equivalent of a normal man touching radioactive rods from a nuclear reactor with his bare skin. Only the element lead can block the radiation, and it is therefore Superman's only protection. Fortunately, Professor Hamilton supplies Superman with a distinctive and durable lead protection suit for such situations.
Kryptonite, in the animated series, still has effects on normal humans as well. There are two examples of this. First, the "Jade Dragon" from World's Finest (a three-part crossover episode between The New Batman Adventures and Superman: The Animated Series) is a statue of Kryptonite carved in the form of a Chinese dragon, said to be cursed because all of its owners all died within a few years of acquiring the piece. Second is Lex Luthor's Kryptonite poisoning/cancer as seen in Justice League, attributed to Lex's admitted habit of keeping a fist-sized chunk of Kryptonite in his pocket for years. Batman also carries a piece of Kryptonite (possibly the same piece) in his own belt (which he dubs "insurance"), presumably in a lead-lined pouch, as Superman is often seen next to Batman without suffering any ill effects. That piece was later shattered against Superman's chest by AMAZO, leaving only a small needle-like piece left. In Batman Beyond, it was revealed in the two-part episode "The Call" that Bruce Wayne kept the needle of Kryptonite for the rest of his life, locked up securely in the Bat Cave.
Green Kryptonite remains the only variety of the substance ever seen in the DC animated universe.
Krypto the Superdog 
As mentioned above, the Krypto the Superdog episode "Streaky's Cat Tail" features "purple-spotted Kryptonite", which causes Superdog to compulsively chase his tail. However, this was almost certainly a product of Streaky's imagination. Red Kryptonite has appeared and is stated as having weird effects on Kryptonians for a day; it has swapped the minds of Kevin and Krypto, removed Krypto's powers, turned both Krypto and Streaky into fish, and in another episode caused Krypto's tail to become sentient and separated from his body.
Legion of Super Heroes 
Kryptonite also appears in an episode of the Legion of Super Heroes cartoon, where it is revealed Brainiac 5 has a piece of it, and that the villain Drax, who, despite being an analogue to Superman, is immune to it. In the season 2 episode "Dark Victory", a brainwashed Brainiac 5 not only attacks Superman with a Kryptonite ray, but also produces a band of Kryptonite from within him and places it on the hero's head, the band then tightening around it.
Batman: The Brave and the Bold 
Green Kryptonite and Red Kryptonite appear in the Batman: The Brave and the Bold episode "The Battle of the Superheroes". The red Kryptonite exposure causes Superman to turn evil and try to take over Metropolis. Lex Luthor is also shown to have his Kryptonite Ring when he tries to weaken Superman only to discover that Superman is actually Batman in disguise. When Batman finds himself on another world, he gains super powers until Rohtul (a villain similar to Luthor) uses quartz on him to the same effect of Kryptonite on Superman.
Empty Nest 
In the comedy TV series Empty Nest, the pediatrician who is the main protagonist of the show suggests using Kryptonite to treat a boy who admires Spider-Man and dresses up as him. The boy objects that Kryptonite is part of the Superman universe, not the Spider-Man universe. But the doctor is right: Kryptonite would enhance the powers of Spider-Man, or of any Earth human being with powers.
Young Justice 
Video Games 
- Lego Batman 2: DC Super Heroes, features Lex Luthor in the possession of Kryptonite used to power his "Deconstructor": his weapon to destroy the shiny black Lego pieces. Is this continuity, Kryptonite is formed with ingredients: Promethium, Mercury, Xenon, Tantalum, and Dialum.
Kryptonite by 3 Doors Down
- "TvTropes". TvTropes. Retrieved 2010-09-17.
- Tippens, Norman. "Dorothy Woolfolk, Superman Editor", Daily Press (Hampton, Virginia), December 6, 2000. WebCitation archive.: As related by Tippens, who notes, "although there is no definitive record".
- Niven, Larry. "Man of Steel, Woman of Kleenex," All the Myriad Ways (Ballantine Books, 1971).
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- Action Comics #654 (June 1990)
- Countdown to Infinite Crisis
- Superman/Batman #47-48
- Superman/Batman #49
- Action Comics #871
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- Superman: The Man of Steel Sourcebook (1992)
- "The Great Kryptonite Mystery", Superboy (volume 1) #58, July 1957
- Kingdom Come
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- "The Untold Story of Red Kryptonite!" in Superman #139 (Aug 1960). Story by Otto Binder, Pencils by Curt Swan, inks by George Klein.
- JLA #44, August 2000
- Season 2, Episode 20, titled "Individual Responsibility"
- The Season 3, Episode 7, installment titled "Ultrawoman".
- The Season 4, Episode 12, installment titled "Lethal Weapon" had Superman's powers going into overdrive as a result of exposure to red Kryptonite, causing him to become dangerous to friend and foe alike. Superman was warned to stay away until he got his powers under control. Disobeying the Mayor's orders when the culprits were about to escape, he was shot by a Metropolis police sniper with a bullet fastened of Green Kryptonite which weakened but did not kill him. Superman then recovers after the Green Kryptonite neutralized the Red Kryptonite.
- Smallville, Episode 02x04 "Red"
- Krypto the Superdog episode "Superdog? Who's Superdog?"
- Krypto the Superdog episode "Bat-Hound for a Day"
- Krypto the Superdog episode "The Living End"
- Krypto the Superdog episode "Furry Fish"
- Krypto the Superdog episode "Dog-Gone Kevin"
- Batman: The Brave and the Bold episode "The Battle of the Superheroes!"
- Action Comics Annual #10, 2007
- "Smallville - Episode 10x17 - Kent Promo Trailer". YouTube. Retrieved 2011-03-04.
- Smallville, Episode 10x17 "Kent"
- Smallville, Episode 10x19 "Prophecy"
- Smallville, Episode 10x20 "Finale, part 1"
- Action Comics Annual #11 (2007)
- Supergirl #37 (March 2009)
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- Action Comics Vol. 2 #16
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- "Supergirl's Super Pet!" in Action Comics #261 (Feb 1960). Written by Jerome "Jerry" Siegel. Art by Jim Mooney.
- "The World's Mightiest Cat!" in Action Comics #266 (Jul 1960). Written by Jerry Siegel, Art by Jim Mooney.
- Superman Family #203 (1974)
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- Barbara Whiteman (February 2003). "The Man of Steel Carries Kryptonite to Piccadilly" (Press release). Le.ac.uk. Retrieved July 8, 2010.
- "'Kryptonite' discovered in mine". BBC News. 2007-04-24. Retrieved 2010-10-10.
- Jackson Gillis (writer); Thomas Carr (director) (December 5, 1953). "Panic in the Sky". Adventures of Superman. Season 2. Episode 12. Syndicated.
- Jackson Gillis (writer); Harry W. Gerstad (director) (June 2, 1956). "The Deadly Rock". Adventures of Superman. Season 4. Episode 11. Syndicated.
- Jackson Gillis (writer); George Blair (director) (October 24, 1953). "The Defeat of Superman". Adventures of Superman. Season 2. Episode 6. Syndicated.
- Peggy Chantler Dick (writer); Harry W. Gerstad (director) (May 14, 1955). "Superman Week". Adventures of Superman. Season 3. Episode 4. Syndicated.
- Robert Leslie Bellem & Whitney Ellsworth (writers); Philip Ford (director) (February 10, 1958). "The Magic Secret". Adventures of Superman. Season 6. Episode 2. Syndicated.
- David T. Chantler (writer); Howard Bretherton (director) (March 24, 1958). "The Gentle Monster". Adventures of Superman. Season 6. Episode 8. Syndicated.
- Robert Leslie Bellem & Whitney Ellsworth (writers); George Reeves (director) (April 28, 1958). "All That Glitters". Adventures of Superman. Season 6. Episode 13. Syndicated.
- Todd Slavkin & Darren Swimmer (writers) & Allison Mack (director) (2009-01-29). "Power". Smallville. Season 8. Episode 13. The CW.
- Don Whitehead & Holly Henderson (writers) & Michael Rohl (director) (2009-02-05). "Requiem". Smallville. Season 8. Episode 14. The CW.
- Alfred Gough, Miles Millar (writers) & Greg Beeman (director) (2004-09-22). "Crusade". Smallville. Season 4. Episode 1. The WB.
- Steven S. DeKnight (writer) & Terrence O'Hara (director) (2005-04-13). "Onyx". Smallville. Season 4. Episode 17. The WB.
- Al Septien, Turi Meyer (writers) & Tom Welling (director) (2009-05-07). "Injustice". Smallville. Season 8. Episode 21. The CW.
- Brian Peterson, Kelly Souders (writers) & James Marshall (director) (2009-05-14). "Doomsday". Smallville. Season 8. Episode 22. The CW.
- Steven S. DeKnight (writer) & James Marshall (director) (2005-11-10). "Splinter". Smallville. Season 5. Episode 7. The WB.
- Todd Slavkin, Darren Swimmer (writers) & Glen Winter (director) (2007-11-150). "Blue". Smallville. Season 7. Episode 8. The CW.
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