Gatsby Jewellery Ltd has dated this piece to the 1930s.

Accompanied by an independent jewellery report from IGR (#30309252).
Cut – Old mine cut.
Colour – K.
Clarity – VS2.
Carat – 0.65.
Circa – 1935.
Measurements – The diamond is approximately 4.7 x 5.1mm and sits 6.75mm from the finger.
Size – K 1/2 (UK) or 5 3/8 (US). Complimentary sizing is available, can go up or down.
Metal – Tests as platinum.
Gatsby Jewellery Ltd has dated this piece to the 1930s.
Gatsby jewellery are a husband and wife team who have years of knowledge and experience in dealing in fine antique jewellery.
You can view the stock and full dealer information on the Gatsby Jewellery Ltd Profile Page