Gold and Silver worn together?

So today I had the debate of wearing my new silver letterpress necklace and wearing my gold fossil watch. So instead of deciding between the two I put on the gold watch, the silver necklace, a long gold chain and some silver earrings. I might be totally off the mark today, but I actually think it works with my ensemble. What are the rules on silver and gold? Is it wrong to wear both, like brown and black (I wear them together sometimes too)?