The first obituary of 2010 in Germany’s Frankfurter Allgemeine newspaper was headlined “The Elimination of Eternity”. The reference was to “Wittelsbach Blue”, an azure 35-carat diamond that once graced the crown of the Bavarian royal family. After paying a record €19 million at auction for it, London jeweler Laurence Graff has recut the big blue in a more modern, multifaceted manner and put the piece on display in Washington next to the Hope diamond...