Roberto CoinIpanema 18k Gold Square Citrine EarringsDetails18-karat yellow gold. Crisscross bezels hold cushion-cut citrine, 20mm. French wire backs with crisscross fronts. Roberto Coin signature hidden 0. 3-carat ruby. 1 1/2"L. Designer About Roberto Coin: Since founding his own company in 1977, Roberto Coin has rightfully gained fame as a tireless innovator, most notably for pioneering the use of three-color gold in 1978. His jewelry seems to capture the fluidity of his amphibious hometown, Venice-forms and shapes meld, creating a sense of wholeness, the distinction between the timeless and the modern ever-blurred. Perpetually reinventing his personal style, Roberto Coin produces more than 600 unique jewelry models annually. Each piece includes a hidden 0. 3 carat ruby, a signature of the designer.