Kryptonite is a fictional material that appears primarily in
Superman stories published by
DC Comics. In its best-known form, it is a green, crystalline material originating from Superman's home world of
Krypton that emits a unique, poisonous radiation that can weaken and even kill
Kryptonians. Kryptonite radiation can be transmitted through any element except
lead. Thus, Superman has a special lead suit to protect himself from the radiation. There are other varieties of kryptonite, such as red and gold kryptonite, which have different but still generally negative effects.