They're made out of Lusternian carbon-based crystals.

And if you can tell me using the help file's description why tae'dae take MORE damage from magic, then I'll concede the point about why Lucidians can't have magic resistance. (Unless I think of a better point.)

2 Gaetele
PWNED? Hmm, watch your language. In fact, his answer was what I was asking for all the way, and you'll understand it, if you were actually reading my posts.
2 Shiri

Hmm... balance?
Same goes for slow learning, for instance... and, note, I've never mentioned slow learning of lucidians - that's an obvious balancing tool, and good one too - cause it's really imperseivalbe and an easy subject to the suspension of disbelief.
But, I guess, I can explain it anyway - being creatures of low intellect and magic, their auras are really weak - making them voulnerable to magical assault, cause are easy to penetrate. *shrugs*
But in case of lucidians, it's said that their crystalline structure (which means - entire structure, no doubt) gives them resistance to magic. Not just skin, covered with crystal scales... if that was the case, I'm sure that would be noted in the help.

It doesn't say anything about auras in the help file. You just pulled that out of your shoe. Tae'dae are just as good at lowmagic as anyone else, anyway.
Anyway, it must mean the "crystalline structure of their skin." *shrug* If you're going to invent meanings out of nothingness for one thing, you can certainly fit fairly reasonable reasons for other factors in a different race.

Well, you wanted me to do that, didn't you? There is no mention why they have it.

Only if they don't contradict what we have ingame, or what is said in helpfile.

Exactly. But you didn't complain about that. Or any of the other minor inconsistencies that it just has to be assumed are part of Lusternian logic rather than RL logic or standard fantasy logic.

The example I just provided doesn't. *shrug* It interprets, not contradicts.