Today’s earring rendering shows two choices – one in all 18K yellow gold and the other in white and yellow gold. I particularly like combining metal colors. I think it often makes for more versatility (i.e., you could add a necklace or ring in either gold or silver metal to compliment these earrings), and it can make for a richer design overall.
For some stellar examples of the use of bi-metal in jewelry, check out the Cushion line of the late Steven Kretchmer. In fact, take a look at the entire website. Steven Kretchmer was a jeweler extraodinaire, a magician of metals and alchemist of sorts. In addition to his unique implementation of the tension setting in much of his work, Kretchmer’s lasting legacy to the jewelry world includes, in part, the invention of Polarium, a permanently magnetized platinum alloy, and the development of purple and blue golds.