Tiffany & Co. Sterling Silver Rubedo Interlocking Circles Pendant Necklace Tiffany & Co.'s Rubedo bar necklace is made from Tiffany's own Rubedo metal, which is over 55% copper, 31% gold, and other small parts of silver and zinc. The word "Rubedo" is Latin for "red" and the metal gives the necklace a rosy tone that complements silver or gold well.