Lady's Platinum Ruby & Diamond Ring. Contains: One Oval Shape Ruby Weighing Approx 2.26ct. 10 Round Cut Diamonds Weighing Approx 1.18cttw. Color: Colorless/Near Colorless Clarity: VS/SI Containing a natural oval cut Burma Ruby, surrounded by 10 round diamonds, and set in hand-made platinum mounting. Rubies, carat for carat, are the most expensive gemstones in the world. In recent years, it's become almost impossible to find good gem rough that will cut out to two carats, which is the size that an upscale piece of jewelry requires. This stone has everything going for it. It's mounted in platinum (the noble metal), it has a good size, and it has life.