The ever useful Grorgian split ring, perfect for use as a connector, extender, charm hanger, or even as a ring! 
The chased design is typical of the period, and this one has not been over used, so the split is nice and flush. 
Tested as 15ct gold
Weight approx 2.62g 
External diameter approx 22mm
Width approx 2mm
Ring size P
Very good antique condition