OLD MARQUISE DIAMOND RING Description: Marquise ring in 18ct gold (750/1000) and platinum, set with antique cut diamonds, circa 1900. This important old marquise ring is set with old-fashioned cut diamond for a total weight of about two carats. It is of a beautiful size and a pretty shine. The marquise ring is a timeless classic. Very beautiful old jewel. Work of the end of the 19th century, beginning of the 20th.