MOSCOW — Moscow’s new rich have taken a giant stride toward transforming communism’s drab citadel into the world’s new powerhouse of art acquisition.

Their trophy wives, draped in diamonds and Gucci, totter dutifully by their sides. Thousands of Russian millionaires thronged the most lavish art fair held in the country since 1917, hoping to take possession of high society’s latest fashion accessory. In an exhibition hall outside the Kremlin, from where Soviet-era gerontocrats once ruled that socialist realism was the only acceptable form of art, Western dealers hung van Dykes and Warhols to feed a market whose appetite seems to know no bounds.

With a Picasso on sale for nearly $20 million and diamond necklaces going for almost twice as much, the opening of the Moscow World Fine Art Fair on Tuesday was proof that the balance of power in the art world is shifting inexorably eastward.

As her husband shopped for a Renoir for their dining room, Nastya, a 20-something brunette dressed in floating chiffon, had found a little bauble in the jewelry section.

Her husband had restricted her pocket money to just $2 million. The sapphire and diamond necklace, the centerpiece of the Harry

Winston collection, was going for $2.9 million.

“I have ways of twisting his arm,” she said with a laugh.

Though the rows of boutiques seemed to contain every gem a girl could dream of — including a $37.5 million pedant that twinkled with the intensity of the sun — there was the odd trinket aimed at the discerning male oligarch.

A set of gambling chips made by Kristian Stahl, a Swedish designer, was on sale for $1.1 million. Each diamond-encrusted piece came from a meteorite that landed in Lapland 800,000 years ago.

But it was upstairs in the art rooms that records were being broken.

Strolling among old masters and contemporary masterpieces, wealthy Russians admitted that they wanted to emulate Roman Abramovich, who has long been seen as a trendsetter for the country’s rich. Earlier this month, the Chelsea proprietor spent more than $118.5 million on two paintings by Francis Bacon and Lucian Freud.

In truth, the boom began before Mr. Abramovich’s purchases. Nearly 40% of all Impressionist works sold at auction last year were bought by Russians — up from just 3% in 2006.

“As the dollar declines, those countries with strong economies built on energy resources are becoming the new global superpowers of art buying,” said Michael Blanche, an Australian dealer.