Platinum, Gold, Emerald and Diamond Ring, Piranesi. Photo Doyle New York.

18 kt., centering one cushion-shaped emerald approximately 3.96 cts., flanked by 2 trapezoidal-shaped diamonds approximately 1.10 cts., signed Piranesi. Size 6 3/4. Estimate $15,000-20,000

With C. Dunaigre, Switzerland, Gemstone report no. CDC 1310241 stating that the emerald is of Colombian origin, indications of minor clarity enhancement.

Doyle New York. Important Jewelry - Monday, April 28, 2014 at 10am - www.doylenewyork.com