.95 Old European Cut Diamond & Onyx Cocktail Ring in Platinum. 95 Old European Cut Diamond Onyx Cocktail Ring in Platinum. This modern right hand ring features 1. 22 carats of diamonds finished in black onyx and platinum. The center stone is a . 95 carat Old European cut diamond that is bezel set into the center of the onyx. The primary diamond is near colorless and glittering, with milgrain engravings on its bezel setting. Forty nine (49) . 0055 carat diamonds halo the high polished onyx and accent the