Blue lightsabers are traditionally considered a combat or guardian Jedi's weapon. Obi-Wan, Plo Koon, Ki Adi Mundi, Shaak Ti and Anakin are just a few Jedi knights who use blue lightsabers. Both Padawans and Jedi Masters have used blue lightsabers in the movies.
Luke Skywalker's blue lightsaber was changed to green during "Return of the Jedi." The blue Tatooine sky made Luke's original blue lightsaber difficult to see. Green became the standard color for Jedi knights in the prequel "Star Wars" movies. Qui-Gon and Yoda used green lightsabers. After "Return of the Jedi," Padawans and Jedi Masters used either blue or green blades. Green lightsabers traditionally symbolized masters of the force or consular Jedi.
Red lightsabers are Sith dark weapons. Darth Vader, Darth Maul, Darth Sidious and Count Dooku used red lightsabers. Red lightsaber crystals are synthetic Adegan crystals created by the Sith to replace natural Adegan crystals.
The purple lightsaber featured in "Attack of the Clones" was Mace Windu's weapon. Samuel L. Jackson requested a purple lightsaber so his character would stand out during the battle scenes. No other characters in the movies carried a purple lightsaber.
Several other lightsaber colors appeared in "Star Wars" books, comics toys and a variety of Star Wars video games. Cyan, violet, silver, orange and even pink are just a few other lightsaber colors produced by the video game creators.