No filme Superman original , foi descrito como sendo de um meteorito:
The photo shows an ETHOPIAN FARMER holding a wedge-shaped green rock
about a foot long and five inches high. The FARMER grins at the
camera. The caption beneath reads: Meteorite Lands near Addis Ababa,
Ethiopia, June, 1951.
EVE and OTIS stare at the picture, mystified.
EVE
I know I'm going to get rapped in the mouth for saying this, but - so what?
LUTHOR So -what? You mean to us it's just a meteorite? Fair enough.
. .
LUTHOR But because of its high level of specific radioactivity - to
someone from the planet Krypton - this substance would be lethal!
O wiki fornece alguns detalhes sobre uma explicação geral sobre as histórias em quadrinhos:
The amount of kryptonite shown to fall on the Earth in Silver Age
stories is too large to have been evenly distributed from the
explosion of any reasonably sized planet, so the usual explanation for
the large amount that made it to Earth was that the kryptonite and
other materials from Krypton were dragged to Earth by the experimental
warp drive that brought Superman to Earth.
Além disso:
It was possible to artificially create green kryptonite, which the
rogue genius Lex Luthor performed on various occasions. However, he
rarely needed to do so, as kryptonite was so abundant that many
ordinary criminals kept a supply as a precaution against Superman's
interference.