See their true colours shining through....

[Kalimac]

The Blue Wizards are rather the odd ones out, aren't they? The really curious thing for me is that there are two of them when there was only one of every other color - a Yellow or a Red Wizard would have been interesting.

The only symbolic association that I've heard of for blue (except for water and air, as Estelyn mentioned) is honesty and fidelity. Though whether this came after the old rhyme about "Married in blue/You will always be true" or before it I don't know. And unfortunately it doesn't really seem to have much in common with the wizards who disappeared. One random bit of info though, I believe that in British English a good while ago (and maybe even now, I live in the US so have no idea) "bluing" money meant making it disappear. UK Downers, is this right? Maybe the Blue Wizards were just Tolkien's wry comment on his finances...