Kryptonite are radioactive pieces of Clark Kent's home planet, Krypton. For those not in the know about Krypton, though, they're simply referred to as meteor rocks. The rocks had accompanied Clark to Earth during the 1989 meteor shower that had struck Smallville, concealing his spaceship as it had landed in Miller's Field. Kryptonite had also arrived during the 2005 meteor shower, bringing with it Zod's disciples. Kryptonite has had strange effects on the residents of Smallville, as well as the local flora and fauna, mutating the plants and animals while giving humans special abilities. Such meta-humans are known as 'meteor freaks'.

Types of Kryptonite

Green Kryptonite
Appeared: S1 - S10
Most common form.
Lethal to Kryptonians.

Red Kryptonite
Appeared: S2 - S10
Strips Kryptonians of
their inhibitions.

Clear Kryptonite
Appeared: S2 & S6
Neutralized green kryptonite.
Harmless to Kryptonians.

Black Kryptonite
Appeared: S4 & S8
Splits humans and Kryptonians
into two personalities.

Silver Kryptonite
Appeared: S5
Made from Brainiac.
Makes Kryptonians paranoid.

Blue Kryptonite
Appeared: S7 & S9
Strips Kryptonians of
their powers temporarily.

Gemstone Kryptonite
Appeared: S9
Grants Kryptonians
wish-fulfilling properties.

Gold Kryptonite
Appeared: S10
Strips Kryptonians of
their powers permanently.