Official Name: Kryptonite
Nicknames: Green Death; Green Plague; K-Metal; Meteor Rock
Origin of item unknown.
Lead Designer: Lead designer unknown
Additional Designers: Additional designers unknown
Place of Creation: Krypton
First Appearance: The Adventures of Superman (Radio dramatization)
Previous Owners: Lex Luthor; Metallo (John Corben)
Previous Owners (Pre-Crisis): Superman (Earth-One), Metallo (Earth-One), Metallo (Roger Corben)
Current Owner: Batman; Kryptonite Man (K. Russell Abernathy)
History: Kryptonite is the name given to shards of matter cast off from the planet Krypton after its destruction. In the Pre-Crisis Continuity, there were many forms and shades of Kryptonite, but in the Post-Crisis universe there is usually only Green. Whether or not Superman: Birthright and Infinite Crisis will change this remains to be seen.
Exposure to Kryptonite can wield a wide variety of effects depending upon its color and present form.
- Green Kryptonite is the most common form of Kryptonite. It exists primarily as a metallic ore, but can also be found in crystalline forms. The most debilitating aspect of green Kryptonite does not stem so much from the unrefined ore itself, but rather from the waves of radiation that it generates. Exposure to green Kryptonite radiation will greatly weaken a Kryptonian, robbing them of their powers. Prolonged exposure to green Kryptonite proves fatal. Over time, a Kryptonian may develop a slight immunity to the effects of green Kryptonite, but ultimately, green K radiation will poison the body's cell structure resulting in death. Green Kryptonite is also deadly to normal humans, but its effects take longer to fully develop. Lex Luthor once fashioned a small piece of Kryptonite into a gemstone, which he fitted into a ring. After wearing the ring for several months, the radiation produced cancerous growths in his hand, and he was forced to amputate the diseased limb.
- In the continuity of the Smallville television series, green Kryptonite has the same effects on young Clark Kent as it does on his comic book counterpart. Its effects on normal Earth humans is wildly more unpredictable. A regular human exposed to green Kryptonite may suffer from any number of genetic mutations. Some develop temporary super-powers, others goes insane, and some demonstrate no side effects whatsoever.
- NOTE: In Post-Crisis continuity, Kryptonite was formed because natural elements in Krypton fused together to form a new, radioactive element. The ONLY natural form of Kryptonite was green.
- Red Kryptonite was once Green Kryptonite that passed through a mysterious red-hued cloud en route to Earth. Red Kryptonite inflicts random effects on Kryptonians, typically creating an initial "tingling effect" in those affected. No two chunks of Red Kryptonite have the same effect. Red Kryptonite effects typically last for 24-48 hours (though sometimes as long as 72), after which the Kryptonian in question is always immune to that specific chunk of Red Kryptonite. Superman has suffered the following effects upon exposure to various pieces of Red Kryptonite:
- Transformed into a dragon
- Transformed into a non-powered giant
- Transformed into a dwarf
- Transformed into an ant-headed humanoid
- Transformed into a lunatic
- Transformed into an amnesiac
- Rendered temporarily blind to anything colored green
- Excessive hair growth
- Loss of power
- Gained telepathy
- Losing his invulnerability along the left side of his body
- Generated an evil doppelganger (also used in the movie Superman III)
- Unable to speak or write anything but Kryptonese
- Growth of extra limbs
- Loss of balance and manual dexterity
- Mental transference
- Rapid aging
- Personality alteration
- In Post-Crisis continuity, Red Kryptonite does not exist naturally. It first appeared as an artificial construct of Mister Mxyzptlk that eliminated Superman's powers. A second variety was later revealed as a synthetic variant created by Ra's al Ghul, using notes that he had stolen from Batman. That red K was said to have had an accelerated half-life (which caused the color change) and caused Superman's skin to become translucent, meaning he had nothing regulating the intense sunlight he was absorbing.
- The Red Kryptonite that Batman created is similar to the Red Kryptonite in the Lois & Clark: The New Adventures of Superman television series, in which Red Kryptonite causes Superman's powers to become uncontrollable.
- On the TV series, Smallville, Red Kryptonite causes severe changes in Clark Kent's personality, becoming rebellious, unpredictable and acting purely on erotic and selfish emotions (lose all inhibitions). In this form, he normally wears a leather jacket and rides around on a motorcycle.
- In the first comic appearance of kryptonite, the kryptonite seen was red, but had the properties of green k.
First Appearance: Superman (Volume 1) #167
In Pre-Crisis continuity, Gold Kryptonite is one of the more rare variations of Kryptonite found in the DC Universe, and typically exists in the form of a meteor floating through space. Gold Kryptonite has an effective range of two feet, and permanently removes a Kryptonian's super-powers.  In many cases, a Kryptonian who has lost their super-powers to Gold Kryptonite may pass similar hereditary traits to their offspring. As such, their children will not develop superhuman abilities under a yellow sun, as they would had their parents still maintained their powers. This characteristic is not a constant however, and it has been theorized some victims of Gold Kryptonite may be able to sire offspring born with natural Kryptonian abilities. In some situations, the effects of Gold Kryptonite can also rob a victim of his memory, as was the case with the Phantom Zone criminal, Quex-Ul.  A temporary antidote was once developed that negated the effects of Gold Kryptonite for a short period of time. Superman once encountered Gold Kryptonite when he had to race against the Flash across the endless reaches of the Universe.  Gold Kryptonite also played key roles in several non-canon stories, including the 1986 tale Superman: Whatever Happened to the Man of Tomorrow?, and later in the Superman & Batman: Generations stories.
- In Post Crisis continuity, Gold Kryptonite only affects Kryptonians from the Time Trapper's Pocket Universe. Superman once visited this alternate reality wherein he discovered that three Kryptonian conquerors had devastated the planet, ultimately conquering it. Superman used gold Kryptonite to remove their powers. Although the criminals were thus apprehended, Superman elected to end their lives by exposing them to Green Kryptonite, as they had destroyed an entire world and were threatening to do so to his own Earth.
- White Kryptonite was apparently harmful to plant-life.
- NOTE: Does not exist in Post-Crisis continuity.
Yellow Kryptonite was part of a hoax masterminded by Lex Luthor.
- First seen on TV's Smallville, The only time it was ever used (to date) on Clark was in the episode "Crusade", when he was re-programmed as Kal-El. Martha Kent placed a chunk of Black Kryptonite (given to her by Dr. Swann's assistant, Bridgette Crosby) on his chest and the two personalities physically fissured. Clark then used the Black Kryptonite to eliminate Kal-El.
During certain circumstances, perhaps only at time of creation, Black Kryptonite can also affect humans, causing them to split into two different beings, one manifesting a good and pure personality, and the other an evil personality. The only case of it ever affecting humans occurred in the episode "Onyx", when an experiment with Green Kryptonite went awry and caused Lex Luthor to split in two.
- In Post Crisis continuity, Black kryptonite was recently used by Lex Luthor at the behest of Darkseid to expose Kara Zor-EL's true "nature"
- Only seen on TV's Smallville, Silver Kryptonite is an artificial form of Kryptonite created by Professor Milton Fine (the human alias of the Kryptonian artificial intelligence known as BrainIAC, Brain InterActive Construct) using Green Kryptonite and the liquid metal that his body is made of. When Clark is pricked by this artificial form of Kryptonite, he begins having paranoid delusions and becomes convinced that his friends and family are out to destroy him. Silver Kryptonite causes hallucinations, such as an imagined conversation between Clark and Professor Fine, and delusions that what is actually occurring is, in fact, something much more sinister.
- In Superman's Pal, Jimmy Olsen #70, silver kryptonite is part of a joke played by Jimmy to celebrate Superman's silver anniversary. It does not have any powers, it is just a prop.
Blue Kryptonite in Pre-Crisis continuity, Superman once used a Bizarro Duplicator Ray on a piece of Green Kryptonite transforming it into Blue Kryptonite. He then used the altered Blue Kryptonite to halt an army of advancing Bizarros. Blue Kryptonite only affects Bizarros and is harmless to humans and Kryptonians. 
- In Post-Crisis Continuity, like Bizarro himself Blue Kryptonite is opposite to the more common green variety, it will make kryptonian based Bizarros (see Batzarro) highly intelligent (up to 12th level intellect) a process that seems to scare Bizarro and his ilk.
- Post Infinite Crisis Blue Kryptonite appears to have reverted back to it's original form as it has been seen (as of Action Comics Annual #10) to affect Bizarro in a painful manner reminiscent of the effect that Green Kryptonite has on Superman.
- Blue Kryptonite was introduced in the seventh season of Smallville. It strips or rather suppresses Clark's powers, at least for a time. During this time Clark was also immune to the effects of Green Kryptonite. It was forged into Jor-El's victory ring which was presented to him when he first became a member of the Kryptonian Council. Clark's resurrected mother Lara Lor-Van gave him the victory ring, telling Clark that it was a Kryptonian tradition to pass the victory ring onto the first born son when he came of age. The ring had been a trap set by Zor-El, to strip Clark of his powers. Since on their own homeworld kryptonians have no powers, Lara had no way of knowing that blue kryptonite would strip Clark of his abilities.
In Supergirl #79, when Linda Danvers takes the original Kara Zor-El's place and arrives in the Pre-Crisis era, there is a comical scene where Superman is apparently exposed to Pink Kryptonite, with the implication that it temporarily turned him gay.
In an early appearance of kryptonite (Adventure Comics #171, 1950), the kryptonite that appeared was purple, but it acted like green. Some speculate that purple may have been an incredibly rare version of kryptonite that disappeared, but the chances of this are unlikely and it is most likely because of writer's indecision over color.
Kryptonite-X or Kryptisium
Professor Hamilton coined this term to refer to the change that occurred to the Kryptonite that the Cyborg Superman blasted the Eradicator with when it passed through the latter and struck Superman. Instead of being lethal, it restored Superman's powers. Unfortunately, it also apparently clung to him and caused him to absorb solar energy at a rapidly accelerated rate, eventually causing his powers to go out of control and his body to build more mass. Superman was purged of it after battling the Parasite. Not to be confused with X-Kryptonite.
Slow Kryptonite is a variety of kryptonite produced by Metallo that affects humans. Why it is called "Slow Kryptonite" is because the rays sent out by normal Kryptonite are "fast" (high in frequency) and synced with the accelerated kryptonian body. Slow Kryptonite, which releases "slow" rays, is synced with a slow human body, allowing it to affect it.
Kryptonite Plus was a batch of 30 or so multi-colored stones that were left behind by aliens, who said that they were "Kryptonite Plus" or Ultra-Kryptonite. They were actually Tikron stones.
Magno-Kryptonite is a variation of kryptonite that tracks objects from Krypton. It apparently affects people from Krypton as well, and not even the strength of Superman or Bizarro can escape.
Jewel Kryptonite possesses the ability to amplify the psychic powers of people in the Phantom Zone.
Anti-Kryptonite does nothing to harm super-powered Kryptonians, but has the same effects of normal green k on non-super-powered Kryptonians. Also, Ultraman of Earth-Three absorbed the radiations of Anti-Kryptonite to gain superpowers.
Bizarro Red Kryptonite
This variety affects humans the same way red kryptonite affects kryptonians.
X-Kryptonite (in Pre-Crisis only) is a synthetic kryptonite that granted Streaky superpowers.
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 Green 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 green Kryptonite or not Kryptonite at all.
Purple Spotted Kryptonite
A fake kryptonite in the Krypto the Superdog cartoon, this variety made Krypto chase his tail.
Seen in an episode of 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!"
Although not the official name for it, Living Kryptonite is kryptonite or kryptonite radiations that have bonded with a body. Jimmy Olsen, Kryptonite Kid, Kryptonite Man, and Kryptonite Dog have all been bonded to Living K at some point in their lives. The first was relieved of his radiations. It has been theorized by some that the reason Post-Crisis kryptonite causes cancerous growths in humans is because Living K is spawned in the body due to intense exposure to the mineral. This causes the dangerous side effects. However, this theory has not been proven.
A synthetic kryptonite created by Brainiac that mutated Superman, this variety made him grow a third eye on the back of his head. Superman tricked Brainiac with his mutation, however, as he waited for his return (he went into space to monitor the change) and allowed everyone on Earth to believe the k made him go mad, as he would never appear without a hat, and he would act out a hat's properties to solve crime. He also used this to cover his eye. Brainiac attacked Superman with a dunce cap, but Superman used the force of all three eyes to use his heat vision to dissolve Brainiac's force field. He then took Brainiac into custody. It appears the green k in red/green kryptonite does nothing, although the mutation did last longer than 24 hours, perhaps indicating the green k amplified the effects.
- The Kryptonite concept was first developed by Superman co-creator, Jerry Siegel for an unpublished Superman story. In Siegel's original vision, the deadly mineral was known as K-Metal.
- The first use of Kryptonite was actually in an unaired episode of the Adventures of Superman radio dramatization. The first comic book appearance of Kryptonite was in Superman (Volume 1) #61.
- Kryptonite can be used as a powerful energy source.
- Action Comics
- DC Comics Presents
- Superboy (Volume 1)
- Superboy (Volume 2)
- Superboy (Volume 3)
- Superboy (Volume 4)
- Superboy and the Ravers
- Super DC Giant
- Supergirl (Volume 1)
- Supergirl (Volume 2)
- Supergirl (Volume 3)
- Supergirl (Volume 4)
- Supergirl (Volume 5)
- Superman (Volume 1)
- Superman (Volume 2)
- Superman (All-Star)
- Superman Family
- Superman, Adventures of
- Superman: Man of Steel
- Superman: Man of Tomorrow
- World's Finest (Volume 1)
- Krypton (Silver Age)
- Krypton (Modern Age)
- Kryptonite Dog
- Kryptonite Kid
- Kryptonite Man
- Superman (Earth-One)
- Superman (Earth-Two)