RING Yellow gold and silver, set with an oval sapphire weighing approximately 3.80 cts in a surround of round old-cut diamonds. Circa 1900. An old cut diamond, 18k gold and silver ring set with an oval shaped sapphire weighing approximately 3,80 cts. Circa 1900. RC : Probably Ceylon, unheated. Stone size: 9.8 - 8.5 x 5.9 mm approx. TDD: 55; US: 7 1/2 (changeable). Gross weight: 6.8 g (18k - 750 and Agt - 925).