R&B superstar Beyonce Knowles may have the biggest and
most expensive diamond engagement ring in the world, but that doesn’t mean she owns the world’s most expensive diamond. The
most expensive diamonds in the world are decades or centuries old—many have been passed from estate to estate, from museum to museum for generations of diamond lovers to gawk at. Blue, pink and other fancy colored diamonds are among the rarest diamonds, and so it is not surprising that many of the world’s most
valuable diamonds are not D-grade colorless but brightly colored in a rainbow of gorgeous, and pricey, hues.