GENEVA, Switzerland (AP) -- A diamond necklace believed to have been made for 18th century Russian empress Catherine the Great fetched over $1.5 million (euro1.3 million) at auction Thursday night in Geneva, but sold at just below the high-end estimate.Some 200 collectors and dealers of rare jewels packed into Sotheby's auction room for the sale at the city's plush Le Beau Rivage hotel.Sotheby's executive director David Bennet said the auction house was "not really surprised" that the diamond necklace was sold for under its estimated worth, saying "we had put a full estimate on it.""It's the most important historical necklace that we have sold at Sotheby's" in 30 years, said Bennett, who was auctioneer of the sale.In total, over 340 lots were sold for 35.8 million francs ($27.0 million; euro23.1 million) during the daylong auction.The most expensive of the jewels -- a pink diamond ring -- sold for 5.17 million francs ($3.90 million; euro3.34 million).'A rare survivor of the 18th century'But some collectors lamented what they called inflated prices, saying they more reflected the allure of famous names from history than actual market prices."When you sit here, it looks like the market is good because many private buyers are here," Milan dealer Isaac Nessim said. "But this is not reality for a dealer. It is almost impossible to buy a piece here."Sotheby's did not disclose the names of most buyers, many of whom purchased items anonymously. It also refused to identify the former owner of the famed diamond necklace, saying only that it belonged to a lady from a "noble family."Catherine II, or "the Great," was one of 18th century Europe's enlightened despots, known as much for her correspondence with French philosophers Diderot and Voltaire as for the reforms she introduced into Russian society and government. The self-described "philosopher on the throne" ruled as Russia's tsarina between 1762 and 1796.The necklace, which holds 27 large cushion-shaped diamonds, is believed to have been made for Catherine during the beginning of her reign and was housed in the Russian state diamond fund in St. Petersburg until 1917. It includes a matching bow clasp.The piece "is a rare survivor of the 18th century, when jewels were usually broken up to produce new jewelry in the latest styles," Sotheby's said. "Its survival, in its original state, is almost unheard of outside royal or museum collections."On Tuesday, rival auction house Christie's also held an auction of magnificent jewels in Geneva, fetching 51 million Swiss francs ($38.5 million; euro33 million) for over 280 lots.Ten pieces sold for over $1 million (euro857,000), and the most expensive jewel in the collection -- a crown set with diamonds -- went for just under 8 million francs ($6.1 million; euro5.2 million) -- the highest price ever for a crown at auction.Another record was set for the price of a single pearl, when the drop-shaped "La Regente" sold for 3.27 million francs ($2.5 million; euro2.1 million), three times the low-end estimate.That pearl, which weighs over 300 grams (over 10.5 ounces), was given by Napoleon Bonaparte to his second wife Marie-Louise in 1811, Christie's said.Four decades later, Bonaparte's nephew, Napoleon III, had the pearl set in a corsage as a wedding present for his future wife, Eugenie de Montijo, who became Empress Eugenie of France.Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.