Locket

  There was a seller on Ebay who had a bunch of these from different parts of the world selling them for between $200 and $300 about 3 weeks ago.  They are supposed to have little pictures in them from different historic sites, they are turn of the century tourist or keepsake items.  I had one that was missing a picture but still had 7 of the 8 originals in it.  mine was from Paris and had different French landmarks pictured in it.  I sold mine for $136 because it was missing the one picture.  From that experience I would say that most of the value is in the original pictures and perhaps you paid about the right price for yours.  On Ebay they are usually titled as vintage or antique (or old) "book locket", perhaps you can search Ebay and see if you can find one similar to yours for sale.