The most successful single-owner jewelry sale in the United States this year was held on April 28, 2004, when the estate of the late Françoise Hermann was auctioned off in simulcast between the Los Angeles and San Francisco galleries of Bohnams & Butterfields.

Hermann, a jet-setting socialite and philanthropist born in Paris in 1919, purchased most of her collection prior to 1950, in styles ranging from Edwardian and Art Deco to post-war Retro. The highlight of the auction was an important antique diamond and silver-topped rivière necklace. The piece, which has a provenance that dates back to the Empress Maria Theresa of Austria (1717-1780), was estimated at $200,000 to $300,000. It sold to a UK member of the trade for $831,250.

The auction house realized more than 300% of the pre-auction expectation, reaching a final total of $6.2 million. Other highlights included a pair of diamond drop earrings signed “Cartier, Paris,” which sold for $539,750, and a French Art Deco sugarloaf-shaped emerald, diamond, and platinum brooch, also signed “Cartier, Paris.” The brooch, estimated at $100,000-$150,000, sold for $242,750.

Proceeds from the sale of the Hermann estate will go to a charitable foundation established in her name.