Green Materia is the "Spells" of the game. Like Ice, Bolt, Cure.
Yellow Materia is the "Command" Spells of the game. Like Steal, X-Magic, Deathblow.
Blue Materia is the "Support" Materia. Like Added Effect, Sneak Attack, Counter.
Red Materia is the "Summon" Materia. Like Shiva, Hades, Odin.
Purple Materia is the "Independent" Materia. Like Chocobo Lure, Cover, Enemy Lure.
