GENEVA (AFP).- Geneva's autumn jewel auctions got underway Tuesday, with Russian oligarchs and Chinese billionaires among those eyeing up the array of eye-wateringly expensive bling on offer.

The Swiss city's twice-annual sales of rare jewels are often dominated by stones the size of door-stoppers.

But this week, gems valued by their weight in carats will share centre stage with gems enriched by the weight of history -- including Russian diamonds that reputedly helped broker peace between warring empires three centuries ago.

Christie's kicked off the sales at the luxury Four Seasons Hotel des Bergues on Lake Geneva, with an anonymous telephone bidder snapping up the most closely-watched item -- a pair of Boehmer and Bassenge earrings -- for a cool $17.61 million (16.42 million euros) including commission.

Tobias Kormind, head of the 77 Diamonds firm that tracks the global diamond market, said elite collectors are more attracted to loose stones rather than show-stoppers like the earrings, composed of two flawless white diamonds weighing 52.55 carats and 50.47 carats.

"These earrings are far more likely to be a gift for someone to wear for special occasions," he said ahead of the sale, noting that the list of people interested in socialising with more than 100 carats worth of diamonds on their ears is limited.

The earrings fell a little short of the expected price, valued by Christie's at $20-$30 million.

A necklace made of three huge diamonds by the same jeweller went under the hammer for $8.06 million.

'Peace-making' diamonds
Rival Sotheby's takes its turn on Wednesday across the road at the five-star Hotel Beau Rivage.

Among Sotheby's showcase offers is a parure featuring diamonds once owned by Russian empress Catherine I that were given to her by her husband, czar Peter the Great, who led Russia until his death in 1725.

In 1711, Catherine was worried that a raging conflict with the Ottoman Empire posed an existential threat to Russia and ordered her husband -- in the middle of the night -- to draft a peace treaty, Sotheby's said, citing historical records.

Without telling Peter, Catherine sent the peace proposal and all the jewels she was travelling with to the Ottoman Sultan Ahmed III.

The Sultan "accepted these and was obviously delighted, and the truce was given and the (Russian) empire was saved", David Bennett, head of Sotheby's International Jewellery Division, told AFP.

The parure featuring Catherine's diamonds is expected to sell for between $3 million and $5 million.

In an auction heavy on Russian imperial treasures, Sotheby's is also offering a diamond necklace with a detachable clasp owned by empress Catherine II -- Catherine the Great, who ruled Russia from 1762 to 1796. It is similarly valued at up to $5 million.

$180 million of bling
Nothing sold on Tuesday night came close to the eye-popping records set by coloured stones at recent sales.

Christie's set the current mark in May, selling the 14.62-carat "Oppenheimer Blue" for $57.54 million.

That beat a record set a year ago by Sotheby's, when Hong Kong billionaire Joseph Lau bought the 12.03-carat "Blue Moon of Josephine" for $48.4 million.

Christie's is aiming to capitalise on the still-solid coloured stones market with a 9.14-carat Fancy Vivid Pink estimated at $16-$18 million.

The rare "Fancy Vivid" classification is awarded by the Gemological Institute of America to signify a stone's exceptional colour and clarity.

Sotheby's top coloured gem going under the hammer this week is the 8.01-carat "Sky Blue Diamond", with a pre-auction estimated price of $15-$25 million.

Sotheby's has estimated its 342-lot auction at a total of $100 million, while Christie's is offering 220 lots, with an estimated value of $80 million.


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