hmmm what to engrave....

Somewhat bizarrely, Becky is allergic to pretty much all metals except
silver, even regular gold of any purity, *except* white gold.

I think she's just being awkward ;-)

 

LOL

 

Odd! Platinum ought to be OK. Silver is often of a higher purity than
gold, which will often contain a fair amount of copper, (which can be
helpful, making it a bit harder). Someone else commented that white gold
is coated with something, so maybe that's protecting her.