1.23 Mid-Century Emerald Cut Diamond Engagement Ring in Platinum1. 23 Mid Century Emerald Cut Diamond Engagement Ring in Platinum. This GIA certified, Mid Century engagement ring features a 1. 23 carat emerald cut natural diamond in platinum. The facets of the emerald cut stone are rectangular and elongated, offering an abundance of brilliance and sparkle. The center stone is accented by two . 15 carat baguette diamonds on both sides. The primary diamond is prong set and finished in a durable platinum band. From