From top: Nazgol Jahan, Rahul Kadakia and Naval Bhandari.

Jewelry auction houses bring to mind wealthy dowagers trading in pearl strands, but a new generation of New York experts is refashioning the houses’ stodgy reputation. “Just as you have a real-estate or a stock portfolio, you should have a jewelry portfolio,” says Nazgol Jahan, 32, the worldwide director of jewelry at Phillips de Pury & Company. Since her 2005 appointment, she has differentiated Phillips from its competitors by focusing on contemporary designs with affordable price points (from $2,000) that appeal to a younger, more fashion-conscious clientele. “There’s something for everyone at our auction,” says Jahan, who handpicked the jewels set to appear in the house’s inaugural jewelry sale on December 8, at Phillips’s new uptown gallery in New York. She moonlights as a designer as well, commissioning pieces for clients who are often inspired by Jahan’s signature jewels, such as her diamond-encrusted butterfly earrings.

Rahul Kadakia, 36, Christie’s Americas head of jewelry, admits he can’t wear any of the roughly $25 million worth of jewels sitting on his desk, which are destined for the house’s October 20 sale in New York. (The Bulgari Blue, a dramatic ring with a 10-plus-carat, triangle-shaped vivid blue diamond that took Kadakia two years to woo from a European collector, is expected to fetch more than $12 million.) Kadakia joined Christie’s, the No. 1 jewelry-selling center in the world, at 22 as a trainee and whirled through the ranks of its European offices. In 2004, at age 30, he took over the New York department and for three of the past five years has kept annual sales above $100 million. “I brought the market here,” the rainmaker says, adding that his goal for 2010 is $120 million. “We broker deals for some of the most important diamonds in a very discreet manner,” says Kadakia of Christie’s private sales. In the spring he flew to the Middle East to sell the world’s largest marquise-cut D flawless diamond, a 90-carat gem, for roughly $15 million.

Major stones are also the currency of diamond guru Naval Bhandari. As vice president of sales for Sotheby’s Diamonds—a partnership launched in 2005 between the auction house and the Steinmetz Diamond Group—Bhandari, 36, peddles rare and important diamonds that creative director James de Givenchy transforms into bespoke jewelry. “We’ve married them with art, creating these one-of-a-kind objects that are edgy, contemporary, and very luxurious,” Bhandari says of the pieces, some of which include unorthodox materials such as rubber, wood, and steel. (They start at $50,000 and run into the millions.) He curates his clients’ collections too, by searching for pieces to enhance their holdings—such as the Duchess of Windsor’s iconic Cartier flamingo brooch, to be sold at Sotheby’s in London on November 30. “Other luxury items wear out or become outdated,” he says, “but there are few objects that surpass a diamond’s perfection.”