Today is Star Wars Day, according to some marketers who work at Disney. You can celebrate by choosing your own lightsaber color.
This chart shows all of the known colors in the Star Wars universe, along with what we know about the characters who typically use them.
How lightsabers get their colors
In the Star Wars universe, lightsaber colors are determined by the force of the Jedi using a lightsaber. More specifically, as noted on the official Star Wars site, lightsabers come from Kyber crystals, typically found in the frozen caves in the world of Ilum, which acquire color once attuned to a specific Jedi. (There are exceptions, however: At some points, lightsaber crystals were replaced by Kunda stones. More significantly, Sith usually use red-hued synthetic crystals.)
There are some caveats: Many of these colors come from different aspects of the Star Wars expanded universe — movies, books, television shows, comics, and video games — and there may well be inconsistencies between the large number of writers in these various genres. Some accounts of how lightsabers came about may not allow for unusual colors that pop up elsewhere.
Likewise, some of these categorizations may be controversial. Many sources call Tera Sinube's saber white, not silver, though we've charted it as silver above. And the interpretation of the darksaber listed above is, unfortunately, subjective — because it's extremely rare, we don't know how consistently it would fit certain character types (it's also shaped more like a metal sword than a lightsaber).
Other quirks abound, as well — Samuel L. Jackson's character, Mace Windu, probably got a purple lightsaber because Jackson asked for it, not because of some complicated mythology in the universe. And Luke Skywalker's lightsaber was originally blue, and was only changed to green during post-production to make it more visible.
So with all those caveats, are lightsaber colors meaningful at all? It's tough to say, especially since the expanded universe is no longer canonical, according to Star Wars corporate parent Disney. However, the first few colors are definitely symbolic guides to the characters who carry each lightsaber, and as future lightsaber colors are considered, it's likely that previous color choices will be taken into consideration.
All that is a long way of saying, yes, you can gloat that you understand lightsaber colors and your friends don't. Now choose the one that suits you, and may the force ... well, you know the rest.