Large Oval Ruby & Diamond Halo Ring PlatinumLarge Oval Ruby Diamond Halo Ring Platinum. This marvelous modern cocktail ring features a striking 6 carat ruby which is prong set and surrounded by 2. 28 carats of diamonds. Finished in platinum, this fine cocktail ring has an interesting diamond halo with two (2) . 29 carat trapezoid cut diamonds and ten (10) that are Round Brilliant Cut. The diamonds add plenty of sparkle to the fabulous red of this luxurious ruby.