18K FRENCH ART NOUVEAU OPAL PLIQUE-A-JOUR RING: Ca. 1900-1910. One navette shaped cabochon cut crystal opal measuring approx. 20.00 x 5.40 x 3.41 mm and weighing approx. 2.05 Ct. The opal is transparent with rolling blue/green play-of-color, somewhat directional (20%), brightness level of 2.5 Twenty (20) early round single cut and old mine cut diamonds measure an average of approx. 1.00 mm (smallest) to approx. 2.00 mm (largest) Total diamond weight: Approx. .20 Ct. The diamonds average VS-SI2 in clarity and H-I-J in color. Surrounding the opal is stylized foliate motif with plique-a`-jour green enamel. The enamel has hairline cracks in some panes. The opal is bezel set. The diamonds are bead set. Weight: 5.6 grams. French Hallmark. Size: 6.5 Sold with current Florida Diamond Appraisers GIA graduate's appraisal for $3500.