FREETOWN (AFP).- Sierra Leone said Wednesday that it was extending the bidding for a massive 709-carat diamond found by an Evangelical preacher last month, after the government received only six offers for the gem.

Bids will now be accepted until May 10 -- in particular to allow more time for potential buyers from Belgium, Israel, South Africa and the United Arab Emirates, a government spokesman said -- with the auction to be held the following day.

The diamond was unearthed by Emmanuel Momoh, a 39-year-old pastor who is also one of hundreds of so-called artisanal miners in Kono, Sierra Leone's key mining district.

"I also had an opportunity to escape with the diamond to Belgium through a local dealer, but I was convinced that the government is committed to helping our people, so I handed it over to the government," Momoh said at a press conference in Freetown on Wednesday.

"I have been part of all the processes in the weighing, bidding and cleaning of the diamond, and it has been transparent, and I'm very satisfied with the process so far," he added.

But the Sierra Leone authorities lack the necessary equipment for properly cleaning and polishing the uncut stone, which currently appears to be coated by a reddish stain.

The Ministry of Mines and Mineral Resources said it had tried to clean the diamond "by boiling (it) in hydrofluoric acid and nitric acid for 72 hours," but it was not enough to be able to set an accurate estimate of its value.

"We had to do with what we have to ensure that the diamond is sold with quality to the highest bidder as soon as possible," said Sahr Wonday, director general of the National Minerals Agency.

"We want more individuals or companies to bid for the diamond so that we can get the best price" for what is expected to be between the 10th- and 15th-biggest diamond ever found, Wonday said.

The government has pledged to hold a "transparent" bidding process, mindful of the history of cross-border diamond trafficking that fuelled Sierra Leone's civil war from 1991-2002.

Such "blood diamonds" were often found by enslaved members of the population, who were killed or maimed by rebel groups if they refused to dig.

"The president is keen to use proceeds of the diamond to develop Kono and other parts of the country," said Abdulai Bayratay, the government spokesman.

Momoh is the still the official owner of the diamond, but it is unclear what percentage of the sale price he will have to pay the government in taxes.


© Agence France-Presse