Crispin Jewellery has dated this piece to the 1920s.
This piece is most likely made in France
HALLMARKS
Not Hallmarked so tests as

MEASUREMENTS
Central Old cut diamond; 2.5mm.
Old rose cut diamonds; 1-1.5mm
Calibre cut sapphires; 1.5mm
Ring head; 20 x 10mm
WEIGHT
2.8g
CONDITION
Good condition, wear commensurate of age. A beautiful and sought after traditional design. Not a reproduction.
RING SIZE
GB O 1/2 US 7/12
Crispin Jewellery has dated this piece to the 1920s.
You can view the stock and full dealer information on the Crispin Jewellery Profile Page