Dear Claire Claire,
There was a time when mixing gold and silver was not considered good taste...however, fashion is more flexible now.
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Here is what I would do: Stand in front of a full-length mirror in your outfit, and you will then know if it works. If the gold overpowers the delicacy of your crystals and silver, that will be obvious.
However it may be your formal outfit is a stunning tapestry of white-crystal-silver embellished by subtle gold, which lights up the whole room and the whole evening.