One traditional that has been well and truly broken in recent years is the mixing of metals. I can remember being told that you wear either your gold jewellery or your silver jewellery but you don't wear both together.
This seemed to be especially true with rings, gold or silver but not both. In fact it was almost seen as a bit declasse to wear two different metals at the same time.
Gold and Silver Striped Viking Weave Bangle (currently in an Art Gallery)
Well, as I said at the beginning, that "tradition" is now well and truly broken. Mixing metals has now become popular, and as you can see from my pieces listed here, metals can now be found mixed together in the same piece of jewellery.
So what metals do you like mixing together?