The Coupland: Retro Era Antique Engagement Ring with Diamonds. The ring centers on a 0.10 carat old mine cut diamond with an approximate Gemological Institute of America clarity grade of Vs1 and a color grade of J. The center is set in an interesting retro mystery style box with a single old cut round on either side of the center. The ring is crafted in 14 karat white and yellow gold and is currently a finger size 6 1/2 yet can be adjusted to any finger size for an additional charge.