Is Kryptonite made from the element Krypton?

If not, what IS it made of? (And where can I get some?)

Superman (1941)

Voices: Up in the sky, look: It’s a bird. It’s a plane. It’s Superman!

Narrator: [opening narration]

  • “In the endless reaches of the universe, there once existed a planet known as Krypton, a planet that burned like a green star in the distant heavens. There, civilization was far advanced and it brought forth a race of “supermen,” whose mental and physical powers were developed to the absolute peak of human perfection. But there came a day when giant quakes threatened to destroy Krypton forever.
  • One of the planet’s leading scientists, sensing the approach of doom, placed his infant son in a small rocket ship and sent it hurtling in the direction of the Earth just as Krypton exploded. The rocket ship sped through star-studded space, landing safely on Earth with its precious burden: Krypton’s sole survivor.
  • A passing motorist found the uninjured child and took it to an orphanage. As the years went by and the child grew to maturity, he found himself possessed of amazing physical powers.
  • Faster than a speeding bullet, more powerful than a locomotive, able to leap tall buildings in a single bound. The infant of Krypton is now the Man of Steel: Superman!
  • To best be in a position to use his amazing powers in a never-ending battle for truth and justice, Superman has assumed the disguise of Clark Kent, mild-mannered reporter for a great metropolitan newspaper.”

Isn’t nostalgia great? I still get a buzz when I read this. I was a kid watching George Reeves dressed in his greyscale Superman outfit (black and white television, kids — it really existed once and you didn’t have a choice) jump out a window and pretend to fly. Didn’t matter it that the background move the wrong way and you could see the low budget effects if you looked hard enough.

It was Superman and none of that other stuff mattered. The only thing I hated about Superman was his unfortunate fate of being driven to his knees by a glowing piece of green rock.

Kryptonite! My first curse word. I hated it.

Every time Kryptonite appeared in a story it drove me to anxiety trying to figure out how Superman was going to escape from Kryptonite this time. Because I knew he would. He had to. Otherwise there wouldn’t be a show on next week.

What were they going to call it? Superman’s Pal, Jimmy Olsen?

The famed Superman’s Pal, Jimmy Olsen number 53 and the science fiction cover which inspired it.

Thus was born my need, my overwhelming urge to know my hated nemesis: Kryptonite. Over the years, I became an authority on the evil stuff. Seeking out stories where it appears, noting the variations and opportunities for mayhem each variety caused.

Noting the times, Kryptonite ever did anyone any good. Okay, one time: White kryptonite was used to save an area from the menace of an invading plant which would have been impossible to kill otherwise. Yep. That’s about it. Kryptonite: bad. So the Answer-Man’s archive has more information about Kryptonite than any sane person needs.

Answer-Man’s Archive: What is Kryptonite?

Despite its name, Kryptonite is not made of the element Krypton. There are a number of versions of Kryptonite over the seven decades Superman has existed, but no matter when it is described, it is almost never composed entirely of the noble gas, Krypton.

  • Krypton (from Greek: κρυπτός kryptos “the hidden one”) is a chemical element with symbol Kr and atomic number 36. It is a member of group 18 (noble gases) elements.
  • A colorless, odorless, tasteless noble gas, krypton occurs in trace amounts in the atmosphere, is isolated by fractionally distilling liquefied air, and is often used with other rare gases in fluorescent lamps. Krypton is inert for most practical purposes.

How did Kryptonite get its name?

Technically, from the planet which exploded and from where Superman was born, the planet Krypton.

  • Kryptonite first appeared on a radio broadcast in 1943 and made its first non-green appearance in 1949’s Superman #61, we would not actually see the signature GREEN Kryptonite until 1951 in Action Comics #161.
  • Kryptonite was needed as a storytelling device to incapacitate the Man of Steel and allow him to have a weakness. (During the radio broadcast where it appears, the actor needed to go on vacation, so Kryptonite was used to incapacitate the Man of Steel until the actor could return. Superman moaned in pain for the episodes and had no other spoken lines.) Up until then, Superman couldn’t be stopped by anything for long.
  • Given when it was created, most people had a very limited scientific background including the writers, thus its name is likely a very simple fusion of an exotic sounding material (Krypton) and the (-ite) suffix which in chemistry denotes a chemical compound.
  • From chemistry: Used to form names of certain chemical compounds, especially salts or esters of acids whose name ends in -ous such as bromite, chlorite, iodite, phosphite, sulfite.

Odds are, this was all the thought that went into it. These writers were on a schedule.

How was Kryptonite described?

  • Kryptonite’s origins vary but most describe its creation at the core of the planet Krypton and were in some continuities responsible for the violent chain reaction which lead to the destruction of that world, killing all of its inhabitants.
  • During the Silver Age, it was theorized the chain reaction could have been stopped but the Green Lantern assigned by the Guardians of Oa, to deliver the stabilizing agent was delayed by a supernova and did not arrive in time. (Tomar Re, if anyone is curious whose to blame for this screw up.)
  • Many pieces of Kryptonite arrive on Earth because they traveled near the space-ship Jor-El sent baby Kal-El to Earth in. Other pieces were thought to arrive later.
  • Some were exposed to various cosmological effects in the Silver Age, Kryptonite came in a variety of colors. Each color had specific capabilities and environmental effects which were caused by exposures to different radiations, natural phenomena or scientific experimentation.
  • Most depictions indicate it was only the core of the planet which was comprised of Kryptonite, though some of the earlier ones indicated any piece of Krypton that came to Earth was considered Kryptonite.
  • Kryptonite is depicted as a radioactive transuranic element or compound (we are never told which for certain). It’s atomic number or compound structure has never been official determined. Okay, there are a few pseudo-scientific attempts at creating a chemical composition but none of them have any basis in reality.*

How does Kryptonite work?

  • DC’s writers have never made an official “scientific” rationalization as to HOW Kryptonite works.
  • Over the decades, we are given a variety of reasons it works, but just vague enough we cannot be exact on the process within his cellular activity.
  • Kryptonite’s inherent radioactivity inhibits the absorption of solar energy which Kryptonians use to catalyze their feats of superhuman ability. Not only does it prevent the further absorption of solar energy, it displaces, painfully, said solar energy with Kryptonite radiation causing the immediate loss of a Kryptonian’s superhuman abilities within seconds.
  • In almost all known continuities, it is Green Kryptonite which has proven to be lethal to Kryptonians who have been exposed to its radiation. Green Kryptonite was lethal to any Kryptonian from the same universe the Kryptonite was derived from.
  • This fact was discovered by Post-Crisis Superman when he was forced to execute the Phantom Zone villains of another Universe after they had killed everyone on Earth. Post-Crisis Superman was immune to green Kryptonite from their universe and was unaffected by its radiations. (See SE Article: In comics how many people have been killed by Superman?)
  • This cellular energy displacement of the stored solar energy with Kryptonite radiation can, depending on the purity and exposure length, lead to the death of a Kryptonian by a form of “radiation poisoning”. A sign the poisoning is complete is the green cast present in the skin of the now dead Kryptonian.
  • A nice analogy to describe the effect of Kryptonite poisoning and how it functions — is in a fashion similar to “carbon monoxide poisoning” where carbon monoxide molecules are being taken up by blood’s hemoglobin instead of the normal Oxygen molecules. The CO is displacing the 02 molecules but does not providing any oxygen necessary for life. With sufficient displacement of O2 molecules a person can die.

Uses for Kryptonite (besides killing Kryptonians)

Kryptonite is described as a highly radioactive substance which can be harnessed for energy in an undisclosed matter:

  • Several of Superman’s foes use Kryptonite as part of their arsenal of weapons including Lex Luthor. Luthor was, in previous continuities, not above using Kryptonite to power many of his exoskeleton weapon systems.
  • Luthor also wore a ring with a piece of Kryptonite embedded in the ring. Mostly just to piss Superman off. Luthor wore this ring until it gave him cancer. For a smart guy, he could be kinda dumb… Said ring was recovered by Superman and given to Batman, as a part of a contingency plan to “stop” Superman should he ever be mind-controlled or have his free will compromised.
  • Metallo has a robotic body whose power-plant uses a hunk of Kryptonite as its power source. Brainiac was also fond of using Kryptonite in many of his schemes including creating a body covered with the material.
  • More modern depictions of Kryptonite only show small amounts of Green Kryptonite on Earth, but some advanced science has been able to duplicate the signature radiation making it capable of being used as a weapon against Superman.
  • In previous versions of the DC Universe, the Green Lantern Corps Power Ring was capable of replicating the radiation signature of a piece of Green Kryptonite, potentially making them capable of defeating or at least engaging Superman, if necessary. It has not been revealed if this ability has migrated to the New 52 or Rebirth reboots of the DC Universe.

*Kryptonite in the Real World (in case you were wondering where that asterisk lead to…)

  • A chemical compound and formula was established for Kryptonite in the movie, Superman Returns in 2006. Luthor described it as: “sodium lithium boron silicate hydroxide with fluorine”. It was later discovered in a mine in Serbia and believed to be a fairly unique compound in nature. This material was dubbed Jadarite.
  • The new mineral, unlike the fictional material in the movie, does not contain fluorine, does not emit electromagnetic radiation, and is white rather than green (although, in the Superman comics, there is a white-colored variety of kryptonite). In all other respects the chemistry matches that of the rock containing kryptonite in that movie. The jadarite fluoresces a pinkish-orange color when exposed to UV light.
By Dungodung — Own work, CC BY-SA 4.0

And there you have it. All the useful things you need to know to use Kryptonite effectively should Superman go rogue and need to be put down. (Even armed with Kryptonite, I’m going to let someone else go first…)

If you didn’t get enough Kryptonite radiation…

If you want to understand the mechanics of how and why Superman folds like a deckchair in the presence of Kryptonite, you can read on to discover: Why exactly does Kryptonite hurt Superman?

The Answer-Man’s Archives are a collection of my articles discussing superheroes and their powers in relationship to their respective universes. You can find other Archives on the Science Fiction and Fantasy Stack Exchange.

Thaddeus Howze is a writer, essayist, author and professional storyteller for mysterious beings who exist in non-Euclidean realms beyond our understanding. Since they insist on constant entertainment and can’t subscribe to cable, Thaddeus writes a variety of forms of speculative fiction to appease their hunger for new entertainment.

Thaddeus’ speculative fiction has appeared in numerous anthologies:Awesome Allshorts: Last Days and Lost Ways (Australia, 2014), The Future is Short(2014), Visions of Leaving Earth (2014), Mothership: Tales of Afrofuturism and Beyond (2014), Genesis Science Fiction (2013), Scraps (UK, 2012), and Possibilities (2012).

He has written two books: a collection called Hayward’s Reach (2011) and an e-book novella called Broken Glass (2013) featuring Clifford Engram, Paranormal Investigator.