I think this is Victorian but it might not be that old.  Old fob watch medal fully engraved to both sides.  One with ST other with MSL 04.5 Winners which I have no idea about. 
The front is 9ct rose gold and is stamped 9ct to the base as shown in the picture.   I think the back is solid silver but cannot find a hallmark on this so unsure.   
Measures approx 3cm in height (including loop) and 2.2cm across, just over 1mm in thickness.  

Please note I am away from 13th July to 22nd July so unable to post during this time.