EDWARDIAN YELLOW GOLD DIAMOND AND BLACK ONYX RING. Old european cut round diamond weighing approx .75 ct. centered in platinum-on-yellow gold square box mount flanked by two triangular black onyx accents on shoulders of shank; setting chased with Art Nouveau/Art Deco motifs. - Ring size: 8. Gross wt: 5 dwt. Estimate $500-700