believe these barrel shaped spirit bottles can date to George IV - Regency period i.e. somewhere in the region of the last decade of the C18 until the end of George IV (1830), and agree they sometimes were found in frames - but always wise to be cautious initially as there are copies of most styles. Large relief diamonds - as seen here - were often a feature on such pieces. Sometimes the shape of the stopper can also help to date, but it's unlikely that you're going to pin an actual date on such a bottle, if that was what you were hoping - antique too, rather than vintage.
Would be helpful if you are able to provide bigger pictures, and if possible let us see a picture of the underside of the decanter - at the moment your pix aren't big enough to see details. Would also be of interest to know the height of your bottle - it won't help remotely with dating, but the more information available makes you glass of greater interest.
Have you looked on line at various shapes etc., and is that why you feel this is possibly Late Georgian?
P.S. the underside of your bottle, if period, should show a very wide but probably shallow depression where the scar was ground away - sometimes these Georgian bottles can actually have a double depression - one slightly less wide sitting inside a wider one.