Kryptonite

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.