Pair of turquoise, amethyst and diamond pendent earrings, Cartier. Photo Sotheby's

Photo Sotheby'sEach surmount of cluster design set with circular-cut amethysts, cabochon turquoise and brilliant-cut diamonds, suspending a detachable drop similarly set with turquoise, diamonds and pear-shaped amethysts, mounted in gold and platinum, post and clip fittings, French assay and maker's marks, signed Cartier Paris. Estimate 18,000-26,000 CHF

Sotheby's. Magnificent Jewels, Geneva | 15 Nov 2011 www.sothebys.com