This setting is a titanium ring with an inlay of mokume gane, which is Japanese for Woodgrain Metal.  Different combinations of metal are possible to choose from in the pulldown menu.  You can reference the Mokume Inlays series of rings to see what the various metals look like. The prongs are white gold and are laser welded to the titanium.  They can hold a round stone or a square Princess cut stone.  The ring in the picture is 4mm wide and has a Princess cut stone.