White crystals in newborns diaper??
Finding them in the diaper is probably a sign that the diaper is too full.
It can (although this is probably unlikely) indicate dehydration (my friend who had a terrible time with BF'ing said that she found those in her ds's cloth dipe and thats what the LC said it meant).
Keep an eye on how much he's peeing, but he's probably ok.
It's probably Sodium polyacrylate, which is what holds the liquid in disposables. Some brands are worse than others, in this regard (I noticed Pampers were pretty bad about this). If you're using disposables, you might have to experiment with some other brands to see if one's better in this regard.
It is probably from the diaper, especially if you're seeing more of it inside the diaper... but when E was born she had crystalized urine in her cloth diaper when she was about 4 days old. i can't remember what they called it, ureic acid, or something like that... they said it was normal and just part of her processing. I honestly can't remember if it was general processing or because she was jaundiced... but either way she was just fine!