Thank you for submitting your item for appraisal. This ladies art deco platinum and gold ring with an oval faceted sapphire of beautiful dark blue colour, surrounded by diamonds, was most likely made in the 1920s. There is a likelyhood that this is a synthetic sapphire, but it might as well be a genuine sapphire. This is impossible to tell just by photos. The estimate is based on similar items sold at auction. I hope the information provided was helpful to you.