As we live in a generation that loves breaking fashion rules, this one of course is already gone for a while. It's actually elegant and trendy to mix different tones of metal together.
Of course that's something that should be done with good taste. It's nice mixing together different tones of gold, or old gold with old silver, shiny gold with shiny silver, but not so much in between.
Layering together silver and gold bracelets and necklaces work really good. In the picture on the left, it was mixed gold in one arm, silver in the other. It works really good because they both are made of shiny metal and have a similar structure. It wouldn't work as good mixing hard chunky bracelets in one arm, with some small and fragile ring bracelets in the other.
It's also common finding jewelry that come already from the store mixing both metals. Here are some examples:
From left to right: Les Gens du Sud, Frederica Salvatore Franchi and Missoni necklaces found at yoox.com.
From left to right: Maiden-Art bracelet, Pilgrin pendant and Vionnet bracelet found at yoox.com.
Leaving behind the old fashion rule allow us to get much more creative about the way we combine our jewelry. Beside being fun and adventurous, also makes your look much more funky and fashionable.