Subject: Can white gold turn yellow

Hi,
  I recently bought a 18K white gold diamond ring for my wife.  She had it
sized and after about a week it started to turn yellow.  I took it back to
complain and was told that it was probably a chemical reaction between her
skin and the white gold.  I am no rocket scientist but I always thought
gold was pretty non-reactive.  What is gold alloyed with to make it white?
Could it, to your knowledge turn yellow which happened in this case?  I
have a feeling I am getting the shaft from the jewelry store.

Thankyou

Re: Can white gold turn yellow