The United Nations Security Council has voted to lift a 2001 ban on the export of diamonds from Liberia.
Liberia must join an international diamond-certification scheme
The ban was meant to stop proceeds from the sale of so-called "blood diamonds" fuelling wars in West African nations.
Correspondents say the UN decided Liberia has made enough progress, but that it must certify diamonds for sale do not originate from conflict zones.
Two years ago Liberia elected its first democratic leader, Ellen Johnson-Sirleaf, since its civil war.
The 15-nation Security Council unanimously passed the resolution, including a provision to review the decision after 90 days, council president, British ambassador Emyr Jones Parry, said.
Nearly half of the world's diamonds come from west, central and southern Africa.
But the lucrative trade fuelled conflicts in countries such as Angola, Congo, Sierra Leone and Liberia, as rebel groups fought for control of diamonds and found willing international buyers to finance their activities.
Mrs Johnson-Sirleaf had pressed for the ban to be lifted, arguing that funds were desperately needed to improve living standards in Liberia.
Unemployment is at 85% in the West African nation, and this is a chance to create much needed jobs and reinvigorate the country's economy, says the BBC's Laura Trevelyan at the UN.
Liberia must now sign up to the Kimberley Process, the UN says, to ensure it does not revert to exporting conflict diamonds.
The international diamond certification scheme, established in May 2000, tracks the origin of diamonds on the international market.
This is the council's second vote of confidence in Mrs Johnson-Sirleaf's presidency. In June it lifted an embargo on Liberian wood.
Mrs Johnson-Sirleaf, who took office in January 2006, was the first woman to be elected president of an African country.