Mid-Century 1.71 Marquise Cut Diamond Engagement Ring in PlatinumMid Century 1. 71 Marquise Cut Diamond Engagement Ring in Platinum. This dazzling vintage engagement ring features a GIA certified 1. 71 marquise cut diamond finished in shimmering platinum. The center diamond is near colorless and glittering, with intricate facets that catch the eye. Designed in the Mid Century era, this ring features four stylish prongs and is accented by two (2) . 09 carat baguette diamonds. From the profile, a sleek basket