By Erika Winters
Rio Tinto's annual Pink Diamonds Tender showcases some of the world's rarest fancy-colored diamonds from the Argyle Diamond Mine in Western Australia. And for the first time in the mine's 30-year history, three rare red diamonds will be offered at the exclusive sale. The largest of the red diamonds is the 1.56-carat Argyle Phoenix, named in honor of the new Argyle underground mine.
