It is solidly decorated with three dimensional repousse work.  The top of the lid has a stamped design, perhaps Turkish, as it is ringed with the star you see on the Turkish flag and the lid is also engraved Constantinople in block letters, an earlier name for Istanbul.  Additionally, the lip is engraved August 1888 in cursive lettering.

The flask is stamped with Gorham's hallmarks, sterling and 455, with perhaps a partially rubbed date mark.