<span class="SFPTagline"> From SCIFIPEDIA </span>

Kryptonite, in the fictional Superman universe, is a rare mineral element and the one of the key vulnerabilities (weakness) of Superman.

When Superman's home planet, Krypton, was destroyed, pieces of the planet were irradiated and flung into space. Some of those pieces made it to Earth, some possibly accompanying the rocket that brought the baby Kal-El (who would grow up to be Superman).

In the most typical scenario, Superman is exposed to green kryptonite. The effect depends on proximity: the closer he is to the mineral (usually shown as a glowing green rock), the weaker he gets. Prolonged exposure would be fatal. Kryptonians who die from "Kryptonite Poisoning" are usually shown with green skin, a side effect of the exposure. The deadly radiation can be blocked by lead.

Earthlings are unaffected by kryptonite, at least in the short term, and can handle it safely. It can also be synthesized, which has been done by Lex Luthor.

During the Silver Age of Comics, the idea of other colors distinguishing other varieties of kryptonite was created. Each different Kryptonite has different effects:

• Green kryptonite is the life-sapping deadly version
• Red kryptonite causes unpredictable reactions (such as becoming a giant or losing one's memory) that are temporary
• Gold kryptonite will remove a Kryptonian's powers permanently
• White kryptonite kills all plant life (Kryptonian or not)
• Blue kryptonite is the Bizarro version: it affects the faulty duplicate Superman known as "Bizarro".

The metaphorical use of the term kryptonite, as a special weakness to an otherwise especially powerful individual, has become mainstream. A front-running politician with low approval ratings for a particular demographic might hear that demographic referred to as their "kryptonite".

Kryptonite in Smallville

The series Smallville expanded on the effects of Kryptonite, though the series rarely refers to the mineral by name. Green kryptonite had its usual effect on Clark Kent, however, it also affected humans. Exposure to meteor rocks caused many individuals to develop superhuman abilities which also seemed to affect their moral center.

Red kryptonite caused Clark to lose his inhibitions, making him prone to spontaneous, rash decisions, and a disregard for rules and others' feelings.

Blue kryptonite had the effect of removing Clark's abilities, making him as vulnerable as a human. It also eliminated the effects of green kryptonite.

Black kryptonite, created by heating green kryptonite, reveals the two psyches within Clark.

Silver kryptonite, created artificially by Brainiac caused Clark to become paranoid and experience hallucinations.