A Chinese face or two in the crowd at the world’s auction houses often means one thing: the gavel will fall on a price far beyond the seller’s wildest dreams.

Fierce bidding by Chinese buyers for a vase at a small London auctioneer in November, for example, drove the price up nearly 40 times beyond its estimate, from around $1.9 million to $70 million.

It was the highest price ever paid for a Chinese artwork sold at auction and equivalent to a huge lottery win for the sellers, who found the 18th Century Qianlong Emperor-era piece while clearing out a house after a relative died.

Christie’s notched up the biggest sales figures in the art auction industry’s history last year, the firm announced Thursday, with record global sales of $5 billion.

And Chinese collectors continued to increase their prominence in the auction rooms as the number of buyers from China, Taiwan and HK accounted for a fifth of the total.

Sales in 2010 were up 53 percent with the firm selling more than half the world’s works over $50 million, including the most expensive painting ever to sell at auction: Pablo Picasso’s “Nude, Green Leaves, and Bust” for $106.5 million.

A painting of sunflowers and a nude by French artist Paul Gauguin is expected to fetch up to 10 million pounds at auction next month, Christie’s said Friday.

Gauguin’s Nature morte à l’Esperance, a still life painted in 1901 when he was living in Tahiti, will be the star lot of a sale of impressionist and modern art in London.

The painting was presented to the media on Friday, the first time it has been seen in public since 1989.

Christie’s International, the world’s leading art business, has launched its new, free App designed specifically for users of the Apple iPad.

The new App takes users on a tour of Christie’s upcoming auctions and enables “at a glance” browsing of hundreds of luxury items and objects to be sold in the company’s salerooms worldwide.

Christie’s offers over 450 auctions annually in over 80 categories, including all areas of fine and decorative arts, jewelry, photographs, collectibles, wine, and more.

A large bronze sculpture of a woman’s back by Henri Matisse sold Wednesday for nearly 49 million dollars, setting a new record for the French impressionist.

Measuring 74.5 inches (189.2 cm), “Nu de dos” was the star of the auction at Christie’s in New York.

It went under the hammer just a day after rival Sotheby’s auctioned an Amedeo Modigliani painting for a record 69 million dollars.

“Nu de dos, 4 etat (Back IV),” had been estimated to sell for between 25 and 35 million dollars, before a bidding war sent the price spiraling to 48,802,500 dollars.

A rare, two-stone ring set a new record price per carat for a blue diamond at auction when it sold for $15.7 million to an Asian collector.

The ring features a 9.87 carat colorless triangular-shaped diamond paired with a triangular 10.95 carat “Fancy Vivid” blue diamond, the largest such blue diamond of this cut ever offered at auction.

The jewel had been bought in Rome in 1972 for $1 million, which is the equivalent of about $5 million today, Christie’s auction house said.