Diamond & Ruby Halo Engagement Ring PlatinumDiamond Ruby Halo Engagement Ring Platinum. This modern engagement ring features a . 39 carat oval cut diamond set in platinum inside a halo of . 64 carats of french cut rubies. The rubies in the halo are calibr cut to fit perfectly to the shape of the center diamond and are channel set between two milgrained bezels. The fine platinum band also contains . 03 carats of round accent diamonds along the shoulders. This is a gorgeous engagement ring for