Im with Gigi on this one.
The crystals are the absorbent part of the nappy usually coming through the nappy because the nappy is so full. So simply changing it earlier will solve the problem.
However, the chemicals in those crystals is not healthy, no matter what the nappy company tells you, so avoid them when you can, if you use disposable nappies. They are the same chemicals they used to use in tampons until they were banned from being linked to toxic shock syndrome. The only way to prevent them altogether is to use cloth nappies.

So dont be overly scared, just change the nappy more often while bubba is weeing so much!! lol