This is likely a chrome alloy ring made around the pre-war era, around the 1920s. It's a ring with a simple and delicate design typical of the pre-war period, featuring a single transparent stone, possibly an old cut glass. It's a masterpiece that doesn't feel old. Size is 13. It has an engraved CROM marking. The condition is good for an antique item, with no distortion or significant blackening. For those who understand vintage and antique items, thank you for your consideration.