This is an antique cushion cut diamond held set into a newer Vintage inspired platinum setting  floating halo style with single cut diamonds all around the main stone and on the shank, accented with milgrain details and subtle knife edge shank. 

The center diamond faces 7.3mm x 6.5mm with a 4.5mm depth, calculated approx. 1.40CT in a K-L color and amazing clarity VS or better clarity, not a single inclusion or blemish can be seen under very high magnification. Single cut diamonds add 0.25CT for a total 1.65CTW. 

RIng is a size 7 3/4 weights 3.02 grams of platinum ( stamped) . RIng faces 12mm x 11.3mm