Gatsby Jewellery Ltd has dated this piece to the 1910s.
The diamond is mounted in a classic six claw platinum collet with an open gallery, leading to a platinum knife edged band.

Contemporary hallmarks, London.
Accompanied by an independent jewellery report from IGR (#30310450).
Cut – Old European cut.
Colour – I.
Clarity – SI1.
Carat – 0.52.
Circa – The diamond is circa 1910, the mount is new.
Size – M (UK) or 6 (US). Complimentary sizing is available, can be sized up or down.
Measurements – The diamond is 5.3mm in diameter and sits 5.6mm from the finger.
Metal – Platinum. Hallmarked.
Gatsby Jewellery Ltd has dated this piece to the 1910s.
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