It was listed by Gatsby Jewellery Ltd. Sold pieces stay on Sellingantiques as a record of what has passed through, and the next one is rarely far away.
Gatsby Jewellery Ltd has dated this piece to the 1920s.

Contemporary hallmarks. London.
Cut – Old mine / miner cut
Colour – J.
Clarity – SI1; the stone is clean to the naked eye.
Carat – 0.65.
Circa – The diamond is circa 1900, the mount in new.
Size – M 1/2 (UK) or 6.25 (US). Complementary sizing is available, can be sized up or down.
Measurements – The diamond is 5.2mm by 5.1mm and sits 6mm from the finger.
Metal – Platinum. Hallmarked.
Gatsby Jewellery Ltd has dated this piece to the 1920s.
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