VINTAGE STYLE DIAMOND ONYX COCKTAIL HALO ENGAGEMENT RING 1ct SETTING ART DECOThis gorgeous semi mount combines striking contrast and a romantic vintage inspired design to create the perfect backdrop for a diamond or gemstone of your choice. The chic design is set with brilliantly white and vibrant natural diamonds and encircled by an elegantly geometric halo of fan shape black onyx. The effect is timelessly stylish and romantic! The bezel setting will fit a round stone that is between 6. 2mm and 6. 4mm with an ideal size of 6.