This is a fabulous sculptural geometric ring, created with cubism patterns, back in the 1970. The rare cocktail ring has been attributed to the Canadian jewelry designer Roger Lucas and has been crafted in solid yellow gold of 18 karats with accents in white gold for the settings of the diamonds. The ring is embellished with an oversized cube carved from blue lapis lazuli and is accented with twenty earth mined natural diamonds. Diamonds: Mounted in flush settings, with 20 European round cut diamonds, approximate 0.40 carats, G/H color, VS/SI clarity. Lapis lazuli: Mount in the center, with 1 cubic cut (15 x 15 x 15 mm) carved from natural blue lapis lazuli, with a weight of about 15 carats. Weight: 25.75 Grams, (16.51 Dwt). Size: 6.5 and can be sized on special request. Measurements: 24 mm by 21 mm (0.95 x 0.83 Inches) and raise 17 mm over the finger. Hallmarks: Stamped with the maker's mark of a palm-leaf inside an oval cartouche and the mark for the assay of the gold as follow, "18KT". Very good conditions. Upon Request, Auction House may provide ring resizing or/and appraisal. This will carry an additional cost. Appraisals are made by our in house GIA certified Gemologist.