Art Deco Aquamarine Diamond Ring. Circa 1930s An 18K gold ring features a sparkling cool blue aquamarine (approximately 2.73 ct) flanked by two platinum panels vertically-set with six cushion shaped diamonds. The shoulders of the ring are embellished with six bezel-set round diamonds. The estimated total diamond weight is 0.30 ct. The ring is marked with French owl mark for imported gold jewelry.