After years of selling vintage jewelry I found that many of my customers decided to collect designer signed jewelry ONLY..How sad. Sad because there are so many seriously beautiful and valuable unsigned pieces.Some of the ones I sold for the highest prices were unsigned. With books and information pointing out construction elements seen in certain designer pieces it's much easier to learn about and recognize them, So collecting old jewelry is even more exciting and fun. You can do some studying and find treasures which are overlooked by many a vintage jewelry collector as well as dealer. Some you may want to check on are listed as follows:  Miriam Haskell, Eisenberg, Hobe' Coro, Mazer,schreiner of New York and of course, Juliana. But most of all, collect what truly pleases you (unless you go into the business of selling old jewelry) and have fun with it all!