2 Carat Mid-Century Diamond Engagement Ring Platinum2 Carat Round Diamond Engagement Ring Platinum. This classic Mid Century square prong diamond engagement ring that features a fabulous 2 carat round brilliant cut diamond at the center and finished in platinum. The shoulders are adorned with six (6) . 04 carat accent diamonds that are bead set, with extremely fine milgrain detail outside of them. This is a clean, classic design made to make the diamond stand out as much as possible.