BALL RING Yellow gold, set with an oval ruby weighing 7.54 cts in a surround of blue topazes. TDD: 53 - 54; US: 6 1/2 - 7 (slightly changeable). A blue topaz and 18k gold ring set with an oval shaped ruby weighing 7,54 cts. Gemological Consultancy certificate attesting: natural colour, no heat. RC : Stone dimensions: 13.13 x 9.90 x 6.68 mm. Gross weight: 12.0 g (18k - 750).