Art Deco Platinum Old Mine Cut Diamond Engagement Ring Circa 1920's. The ring is in great estate condition and ready to wear. The center stone is an approximately .45 carat Si2 clarity L color old mine cut diamond. It is framed by approximately 12 (.36 cttw) transition cut Vs2-Si2 G-H color diamonds. The ring is a size 4.75 and weighs a total of 4.9 grams.