Vintage 14K White Gold Diamond Black Opal Cabochon Ring For Sale at 1stDibs Lot 10K YELLOW GOLD OPAL CABOCHON & DIAMOND RING 18K Rose Gold Ring with Cabochon Opal and Diamonds For Sale at 1stDibs Cabochon Natural Opal Diamond Gold Ring at 1stDibs Round Opal cabochon 14k gold ring. For Sale at 1stDibs. Size 7. 5 Materials: 10K gold, opal Condition: excellent Box shown for display purposes only, not included nor for sale, but ring will ship in a lovely new cushioned ring box that is perfectly suited for presentation. More Vintage & Antique Jewelry here. Select ShopPay at checkout and pay in 4 interest free installments but receive your item straight away!