Web site: https://www.ancient-jewellery.com/
This is a nice Renaissance signet ring, dating to the 16th - 17th century A.D. The ring has a round bezel, decorated with an indistinct device - presumably a mermaid within a shield-shaped cartouche?
A nice historic ring that would have been used by a merchant to authenticate and seal letters.
OBJECT: Signet Ring
DATE: c. 1550 - 1650 A.D.
RING SIZE: 11 1/2 (US) W 3/4 (UK)
SIZE: 24mm x 25mm x 2mm (bezel 14mm x 2mm)
WEIGHT: 3.64 grams
PROVENANCE: Ex. private collection, Brittany, France.