18k Yellow & White Gold 750 Italy Signet Initial Men's Natural Diamond Accent Ring. 

Specs: face 12.3mm north to
south, side band 4mm wide

Ring Size 13

Diamond Accent Specs: 1 round 2.2mm

Weight: 6.2 grams

Hallmarks: 1083 VI, 750 (18k)

any
darkness in ring is due to
camera reflections