A 19th century precious opal and diamond cluster ring, the oval Antique, Art Deco, Platinum, Black Opal and Diamond Cluster Cocktail Quality Natural Opal and Vs Diamond Platinum Cluster Ring For Sale at Antique 18ct Gold Opal & Diamond Cluster Ring ??? Jeremy Silverthorne Opal and Diamond Cluster Ring For Sale at 1stDibs mary skinner. A lovely white gold cluster ring. Features to the centre an oval white opal, 9x7mm, with an excellent play of colour. Retained by claws, and has an outer border of ten brilliant cut white diamonds, each 3mm diameter (estimated total one carat), colour H j, clarity Si. Head measures 14x12mm, depth 6mm, weight 4. 4grams. Purchased overseas, tests as 18 carat white gold, in almost near new condition with no wear at all. Size P, we can resize free of charge.