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 1940s.

Cut - Transitional round.
Colour - Light yellow.
Clarity - SI; diamond is totally eye clean.
Carat - 1.01.
Circa - 1940.
Condition - Excellent.
Size - Currently S (UK) or 9 1/8 (US). Complementary sizing is available, can be sized up or down.
Measurements - The head of the ring measures 9.5mm by 9.8mm and sits 5.9mm from the finger.
Metal - 18k (white) gold. Tested.
Gatsby Jewellery Ltd has dated this piece to the 1940s.
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