Depletion gilding on white gold?

Hi all, I seem to have painted myself into a corner… A couple
commissioned a pair of rings in white gold after seeing a sterling
ring at a gallery. The original ring has small depressions all over
it and has been heated and quenched in acid many times for that fine
silver skin, which is left white in the depressions while the high
spots have been burnished to a polish. What I’m wondering is if
there’s a way of getting that same milk-white surface in the
depressions on the white gold through some easy studio process ( I
tried a bit of heating and dunking in acid but the white gold just
went sort of gray- too much heat? not enough? silly goose chase?),
or if the only way to achieve the same look is to plate with fine
silver over the white gold (this seems to me an odd thing to do) in
order to get that creamy white in the depressions. Any advice would
be much appreciated- thanks! Julia Turner

What I'm wondering is if there's a way of getting that same
milk-white surface in the depressions on the white gold through
some easy studio process ... or if the only way to achieve the same
look is to plate with fine silver over the white gold (this seems
to me an odd thing to do) in order to get that creamy white in the
depressions. 

Hi Julia, I don’t think anyone’s tackled your question, so I’ll
give it a shot. As far as I know, you cannot depletion-gild white
gold. Unlike silver, which is commonly depletion-gilded, white gold
is not alloyed with copper, the element that forms the oxide that
gets pickled away, leaving the fine silver coating behind.

The only way to get a truly white color on white gold that I’m aware
of is to plate it. You wouldn’t use silver, however, but rather
rhodium, which is tougher (and a close relative of platinum). As
long as you disclose to the customer that the piece is
rhodium-plated, it is perfectly acceptable and ethical to do this.
Hope this helps.

Beth