Oct. 4 (Bloomberg) -- A previously unrecorded Faberge egg, an engagement gift to Baron Edouard de Rothschild, may sell for a record $18 million at Christie's International's Russian winter auction in London next month.

The gold and enamel egg, signed by Karl Faberge and dated 1902, is perched on a stand and has a clock with a diamond-set cockerel which pops up every hour and flaps its wings. Christie's estimates the work will fetch $12 million to $18 million at the Nov. 28 sale, well above the $9.6 million auction record set by Faberge's Imperial Winter Egg at Christie's in New York in 2002.

``No one knew about this egg before,'' said Valentin Skurlov, Russia's leading Faberge historian, and an adviser on Faberge to Christie's. ``In terms of quality, it's on the level of an Imperial Egg.''

Faberge was Russia's largest and most prestigious jewelry maker from the 1880s until 1917 when Czar Nicholas II was deposed and the Romanov dynasty ended. Now, Russian collectors are bidding up prices of the country's art as soaring oil and metals prices and eight years of economic growth increase the ranks of the rich.

``We didn't know about this egg before because no one knows the whereabouts of the Faberge company archives,'' said Skurlov. ``The Bolsheviks confiscated the archives of all jewelry companies in Russia to get the addresses of rich people, who they then went after.''

The egg was originally a gift to Edouard de Rothschild and his fiancee Germaine Halphen from the former's sister, Beatrice, Christie's said. Beatrice was the wife of Maurice Ephrussi, who headed the Rothschild oil interests in Russia. Christie's, the world's largest auction house, said the egg has ``remained in the family ever since.'' The company declined to name the seller.

Imperial Easter Eggs

From 1885 to 1916 Faberge made 50 Easter Eggs for the Imperial family. The company also made eggs for wealthy, non-royal clients.

``Non-Imperial eggs have never sold for the estimate that Christie's is asking,'' said Andrei Ruzhnikov, managing partner of Aurora Fine Art Investments, an art investment fund owned by Russian mining and oil billionaire, Viktor Vekselberg. ``Only two of the Imperial eggs sold from the Forbes Collection exceeded that estimate.''

Vekselberg bought the Forbes Faberge Collection of nine Imperial eggs and about 190 other items in a private sale brokered in February 2004 by Sotheby's, for an undisclosed price. At the time, dealers estimated the sale total was around $120 million.

Vekselberg's purchase included the Coronation Egg, which Nicholas II gave to his wife in 1897. The Coronation Egg was valued as much as $24 million by Sotheby's before the sale.