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 1930s.
A winner!

Cut - Cushion shaped Old Mine / Miner Cut, with Rose Cut diamonds in the shoulders.
Colour - I.
Clarity - VS; very clean for an old cut stone.
Carat - Main diamond is approximately 0.75 carat, with a further 0.12 carat in the shoulders.

Circa - 1930.
Condition - Excellent.
Size - Currently M (UK) or 6 (US). Complementary sizing is available, can be sized up or down.
Measurements - The head of the ring measures 7.5mm by 7.5mm and sits 6.8mm from the finger.
Metal - The band and bottom half of the band are 18k white gold. The back plate, claws and shoulders are in platinum. Unmarked, but tested.
Stamps - French hallmarks on the base of the band.
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