The center round diamond is very sparkly, and it measures 6mm (approx .90ct). G/I1. The mounting is very well made and holds both princess cut and round diamonds of approx .75ctw. G/VS2-SI1. 

The ring weighs 5.6g and measures 11mm at its widest point. Stamped and guaranteed to be 18K, but the stamp is rubbed. 

Ring size is 8 and somewhat sizable. I can size it for an additional charge. Let me know if you need a quote.