I have been wondering, is there any evidence of sith / dark jedi, using other colour crystals in their lightsabers other than the classic red?

Canon or Legends (or does it matter)? Quick answer, yes, but in legends.

Exar Kun used his blue lightsaber. Purple is an alternative that some used, potentially yellow or orange.

Only in Legends have we seen Sith use colors other than red in their lightsabers.

Though for the Bane "Rule of Two" lineage of Sith, as well as Krayt's "One Sith" in the Legacy Era, it seems that red was indeed the preferred color, if only to ensure that your opposition knew just how frelled they were.

Thank you for the replies!

I'm not bothered if the source is Canon or not. I was just wondering out loud if it had been done in print. Im in the process of writing the basic outline for my new campaign and I love the idea of a purple lightsaber, I'm not even sure if it is a light or darkside wielder yet!

"There is a sudden 'snap,hiss' and the blade leaps into existence, with a hue of purple so dark, it does not glow but seems to absorb the light, drawing shadows into the room, a menacing bass growl fills the air, so deep you can feel it to your core."

I can't wait !

Maybe equally as interesting for you:

Most lightsaber crystals used by the Sith were artificial, wich gave them the red color. As such Sith that used natural crystals most likely had these in non-red colors.

Adversely there have also been Jedi who used red crystals, though you could probably count them on one hand.

These red crystals were natural however, said to be even more rare than Windus violet lightsaber crystal.

Maybe equally as interesting for you:

Most lightsaber crystals used by the Sith were artificial, wich gave them the red color. As such Sith that used natural crystals most likely had these in non-red colors.

Adversely there have also been Jedi who used red crystals, though you could probably count them on one hand.

These red crystals were natural however, said to be even more rare than Windus violet lightsaber crystal.

I was going to mention that it's certainly possible to have non-red synthetic crystals as well as red natural crystals, but both are exceptionally uncommon.

In the case of synthetic crystals, I believe that they start out as clear and colorless, and it is only through the process of the person aligning the crystal that it takes on a color.

Which would explain why Luke’s synthetic crystal in RotJ produced a green blade, while Vader’s synthetic crystal produced a red blade.

Yeah, the idea that synthetic crystals = red 'saber blades was due to the most common users of synthetic crystals being the Sith, who drew upon the dark side when forming their crystals, thus resulting in the red hue.

As noted by bradknowled, that Luke was able to create a synthetic crystal and have it not be red shows that much like naturally occurring kyber crystals, a synthetic crystal doesn't have a "default" color... at least so long as you're not a dark sider.

Is Luke's synthetic crystal canon? I thought that was all Legends...

I did not know about the hues of artificial crystals, that is very interesting. Thank you.

Is Luke's synthetic crystal canon? I thought that was all Legends...

It may be Legends, now.

But if so, then there is no explanation for why he has a lightsaber with a green blade in RotJ, knowing what we know about how little Jedi knowledge he had at the end of ESB and all the usual sources for crystals that were not available to him.

Even if it is Legends, it could still be a useful piece of information to a GM who decides to make use of that story.

Is Luke's synthetic crystal canon? I thought that was all Legends...

Yeah, it's currently in Legends.

Right now, there's no explanation for how Luke got a hold of a kyber crystal for his new lightsaber. Maybe it's something that will be touched upon in the new films, especially if at some point Rey finds herself needing to construct a new lightsaber.

Maybe Obi-Wan had a few he collected over the years?

Maybe Obi-Wan had a few he collected over the years?

That explanation would be about as good as any other, now that the original Canon answer has since been relegated to Legends status.

To be honest, I would prefer that Luke didn’t make his own synthetic crystal, but instead got a natural one from someone/somewhere else. For me, I think synthetic crystals should only be used by Sith and other darksiders.

However, I know that’s just a personal opinion. YMMV, etc….

Is Luke's synthetic crystal canon? I thought that was all Legends...

Yeah, it's currently in Legends.

Right now, there's no explanation for how Luke got a hold of a kyber crystal for his new lightsaber. Maybe it's something that will be touched upon in the new films, especially if at some point Rey finds herself needing to construct a new lightsaber.

I could swear there was something in the new canon comics - but I won't spoil those for anyone. I don't recall Luke actually finding a crystal, but there were tons of opportunities.

Is Luke's synthetic crystal canon? I thought that was all Legends...

Yeah, it's currently in Legends.

Right now, there's no explanation for how Luke got a hold of a kyber crystal for his new lightsaber. Maybe it's something that will be touched upon in the new films, especially if at some point Rey finds herself needing to construct a new lightsaber.

I could swear there was something in the new canon comics - but I won't spoil those for anyone. I don't recall Luke actually finding a crystal, but there were tons of opportunities.

I would say go ahead and post the spoilers here, with a note that they're such.

Is Luke's synthetic crystal canon? I thought that was all Legends...

Yeah, it's currently in Legends.

Right now, there's no explanation for how Luke got a hold of a kyber crystal for his new lightsaber. Maybe it's something that will be touched upon in the new films, especially if at some point Rey finds herself needing to construct a new lightsaber.

I could swear there was something in the new canon comics - but I won't spoil those for anyone. I don't recall Luke actually finding a crystal, but there were tons of opportunities.

I would say go ahead and post the spoilers here, with a note that they're such.

Now that I've shot my mouth off, I'll have to reread the series I'm thinking of for clarity.