The coolest!  This locket is made to look like a book, it opens and up pops a magnifier and a picture frame.  We've never had one of these!  It's all 18k yellow gold with a diamond.  The locket measures just over 1/2" wide.  The chain is a nice old one, 18k gold and 20" long.  Circa 1910.  
 
 
 jennifer@victoriousincapemay.com