The world's top diamond producer Alrosa said on Wednesday it would float 16 percent of its state and management-held shares as part of the Russian government's teetering privatisation drive.
A stock valuation released by one of the Russian banks involved in the issue has priced the stake at about $1.4-$1.6 billion (1.0-1.2 billion euros).
Alrosa expects "that the offering will expand our access to the international capital markets and help to unlock the value of the company," said company chief executive Fyodor Andreyev.
The gem producer had remained one of Russia's most secretive companies despite its global ambitions and long history of providing the federal government with budget revenues at times of economic malaise.
It is also keen to find the resources necessary to launch new mining projects that would make up for its slowly-depleting Soviet-era base.
Alrosa had said in 2011 that its existing mines would provide it with diamonds for the coming four decades only.
Russia remains a tempting but unpredictable market for foreign investors who are interested in tapping its enormous mineral wealth.
Foreign direct investment has been slowed by a perceived lack of court independence and weak ownership laws that turn investing in Russia into an unduly high risk.
President Vladimir Putin appeared to acknowledge the problem during a speech at a business forum in Moscow in which he pledged once again to pursue overdue structural reform.
"We will follow through on all our intended reforms, including the structural modernisation of entire industries," said Putin.
"We will definitely keep our focus on development and the creation of a strong economy."
Russian media said a fund linked to the founder of the Anglo-American diamonds miner and trader De Beers as well as some top Chinese investors had already expressed interest in the Alrosa shares.
The east Siberian firm accounts for roughly a quarter of the world's diamond production and has reported reserves of 1.28 billion carats.
But the company had been riddled with debt and criticised by analysts for opaque accounting practises.
It reported a 2012 income of $1.0 billion on revenues of $4.7 billion.
Privatisation delayed for years
More than 90 percent of the firm is held either by the state or the local authorities of Sakha -- the diamond-rich region where the firm is based -- while another nine percent is traded over the counter.
Alrosa's partial privatisation has been delayed for years because the state had viewed it as a strategic asset in which foreign ownership was unwelcome and potentially dangerous.
It now represents an important part of a Russian privatisation drive that has been slowed by global economic worries and falling prices on the MICEX exchange.
Putin's government intends to raise about $1.9 billion from state asset sales this year -- a downwardly-revised figure that makes a successful Alrosa flotation vital.
"The company's privatisation ... is a landmark step in the implementation of the government's policy of reducing the state's role in the economy," said Federal Agency for State Property Management head Olga Dergunova.
Alrosa last week agreed to sell some its non-core natural gas assets to the state-held oil giant Rosneft for $1.4 billion as part of its drive to raise funds for new mining investments and pay off debt.
The flotation "is generally a positive for the company because it ... promotes its growth," said Societe Generale's mining analyst Sergei Donskoi.
"But there has been little diamond demand in the past three years," he cautioned. "I put the company's price at the lower end of the valuation."
Russia's federal government will be giving up a seven-percent stake in the company.
The local authorities of Sakha will also give up a seven-percent stake while the other two percent will be sold by a Cyprus-based holding company set up by Alrosa management.