Attached Link: http://www.uvmapper.com

Did you create the crown using groups? (I.e. in the modelling program name the circlet, name the jewels, etc. and export it with the option to use the names?) If so, you can select each group and move it around the map. The standard practice is to select the entire map, shrink it down, then move each group around, resizing each group as necessary. (The jewels might be small since they will be solid colored, while the circlet might be fairly big to accomodate any engravings.) You can also map each group differently: the crown itself as a cylander, the jewels as boxes, etc. There are a few tutorials on UVMapper around, including at uvmapper.com.