Myanmar’s military rulers announced Wednesday their biggest-ever auction of precious gems and jade, saying they hoped to earn at least 53 million euros (63 million dollars) from the sale.

The auctions, normally held every six months, are one of the military’s most important sources of desperately needed foreign currency, although final sales figures are rarely released.

Deputy mining minister, Myint Thein, said some 1,000 buyers from 11 countries would attend the auction — with most merchants coming from China and Thailand.

“This emporium is the most significant in terms of quality, quantity, as well as attendance,” Myint Thein said.

The vast majority of the 2,960 lots, set to go on the block from Thursday, were jade, he said.

But the highlight of the auction will be a spectacular 33.39-carat sapphire, which will go on sale with a starting price of 3.5 million euros (4.1 million dollars), he said.

Viewing of the gems was underway Wednesday, with the five-day sale beginning Thursday.

Myanmar is one of the poorest and most isolated countries in Asia, but has vast natural wealth — including natural gas, minerals and highly prized teak wood — that often disappears into black markets.

The junta began the gems auctions in a bid to curb the smuggling of precious stones out of Myanmar, which deprives the government of much-needed foreign currency.

Myanmar is under stiff EU and US sanctions imposed for human rights abuses and failure to implement promised democratic reforms.

But neighboring giants China and India have increasingly sought to boost trade relations, especially to satiate their ever-growing energy needs with Myanmar’s natural gas fields.