An Art Deco opal, ruby and diamond dress ring, features an oval cabochon of a translucent precious opal with good play-of-colour, displaying bright spectral optical effects on a light ground, approximately measuring 6.7 x 5.2 x 3.0 mm, encompassed with eight single-cut diamonds and four square table-cut rubies, mounted in collet settings with millgrain edge, with tapered shoulders to a flat-sided D-section shank, white metal marked 'S.U.18ct&PLAT', ring head measures 12.8 x 11.8 mm, ring size N½, total weight of item 2.7 grams.