A Circa 1920’s Platinum and Old Mine Cut Diamond Ring with Synthetic Sapphires. Old mine cut diamond center measures 4.8 x 4.5 x 2.94mm and is 0.45cts by formula is I/J color and SI2 clarity. 18 single cut diamonds total 0.32ctw and are G/H color and SI1 clarity. The 4.5mm round synthetic sapphires have replaced diamonds that used to be in this ring, diamonds can be put back in. This ring weighs 4.8 grams and is a size 5.