Not a diamond ring, but a CUP RING! The Cup Ring($45) designed by Japanese Yusuke Fujinuma and Yoko Yamazaki. When holding the cup with all 5 fingers, the handle is conveniently located to fit your ring-finger to showcase the crystal embedded into the handle. If you are in Japan, check the Allabout(JPY 3675), They available in black color cup and crystal ring, I love this color like the pics.
