This is a fabulous vintage ring which dates to the Mid Century Modern Era and was made of 835 silver and hallmarked as such. Most likely Danish or Dutch in origin.
The ring features a blue chalcedony stone suspended between two silver squares. The top of the ring (just the stone) measures 3/8".
VERY GOOD condition! Hallmarked 835. Size 4.5. Probably could fit a slightly larger finger size due to the square shape shank.