PARIS, Oct 7, 2007 (AFP) - One of the world's poorest countries, Myanmar is also home to a hidden treasure: rubies, sapphires and other gems, among the finest in the world, whose trade is thriving despite the political unrest gripping the country.

Shoppers selecting jade and gems jewellries at an exhibition in Myanmar's capital city Yangon Photo : Saeed Khan/AFP

"At the jewellers fair in Hong Kong, gems from Myanmar were on display and the buyers and sellers were all there, none of them looking particularly nervous," said Emmanuel Piat, a top figure of the Paris gem trade.

"For the rarest stones, its true prices have shot up but that has nothing to do with Myanmar," he said.

For the past 700 years, the so-called "Valley of Rubies" in the Mogok region of northeast Myanmar, has been mined for "pigeon blood" rubies -- considered the finest in the world -- sapphires and other rare gems.

A top-notch ruby can cost more per-carat than a diamond, making it a must-have accessory for the rich new elites of Asia, Russia and the Middle East who account for the lion's share of custom on the Paris gem scene.

Last year, an 8.62-carat Burmese ruby fetched a record price of 3.7 million dollars (2.6 million euros) or 425,000 dollars per carat at a Christie's auction.

Imperial jade -- emerald-green in colour -- is another Myanmar treasure greatly appreciated by the Chinese, the main customers for the country's gems.

According to Piat, the Myanmar gem market is split between an official sector, half-controlled by the junta for whom it is a major source of income, and the non-official sector, much of which ends up being smuggled to Thailand.

The stones are mined at a huge human cost, with reports of horrific working conditions in Myanmar's ruby mines, whose access is forbidden to outsiders.

Groups of Myanmar exiles have called for a boycott of the gem auctions held by the ruling junta, claiming that the mines rely on forced labour.

There are reports of soaring AIDS infection rates among mine workers due to needle-sharing among heroin addicts and large-scale prostitution, with drugs shipped in by local traffickers, according to the US group Campaign for Burma.

But according to Piat, a US embargo on stones from Myanmar decreed three years ago has been largely ignored, with the notable exception of the iconic New York jeweller Tiffany's.

Piat said the trade in gems -- from Myanmar and elsewhere -- was continuing undisturbed by the troubles in the country.

The Myanmar junta, which two weeks ago killed at least 13 people as it moved to suppress the largest protests in nearly 20 years, turned up the pressure last week to quell the pro-democracy movement.

If the unrest escalates further, "the per-carat price for rubies could still rise considerably in Thailand, where Myanmar exports its finest stones, legally or illegally," he said.

But more likely to drive up prices was a recent Russian deal to start exploiting uranium in the Mogok region -- creating competition with the gem mines for access to Myanmar's mineral-rich soil.by Francoise Medgyesi