Diamond Flower Tiara of Queen Amelie of Greece. There is a discussion, in German, of the queen and the Oldenburg flower tiara, here: http://www.royal-magazin.de/german/oldenburg/koenigin-amalia-wittelsbach-griechenland.htm It's in German, or badly translated into English, and I don't think it mentions where the tiara is presently, if it still exists.
Gold Earring with pearls and roman gem. Modelled after byzantine artwork. Cologne. Before 1096 pogrom. Found in the remains of the jewish quarter. (Now an official excavation, BTW my working place...I`m a student parttime archaeologist:)