How about something I've done recently. I just finished these rings last week. They are both 18Kt. gold and set with natural colored diamonds. One is two tone, 18Kt yellow and white set with natural yellow diamond and the other one is all 18Kt. yellow and set with natural pink diamonds. This is not a new idea, by any stretch, but they are still beautiful rings. I think the open work on the inside of the bands lifts them to a higher level. The fact that this can't be seen when they are worn adds to the smug comfort of just knowing it yourself.