'It is by the grace of God that you find a diamond'

The rising popularity of lab-grown diamonds has caused a big fall in the price of the mined gems. In the West African nation of Sierra Leone the country's biggest diamond mine has closed.

Stripped to the waist, men toil in the heat of the sun. The mud in the pit is sifted and shovelled.

Daniel, the foreman in this remote, informal, small-scale mine in Kono, the diamond region of Sierra Leone, shows me the gravel he's picking through with his fingers.

"We put it in water and we wash it," he says. "If there is anything like a diamond or any bright stone, we can see it."

Daniel and five others are searching for just tiny fragments, but pickings are thin. "I have not made a lot of money yet," he says. "Sometimes for the whole of the year you can't get anything.

"It is by the grace of God that you find a diamond. We are just dreaming, really. We still have that hope."

Such informal mining has increased in Kono following the closure last year of the country's biggest diamond mine Koidu Holdings. It shut with the loss of 1,000 jobs after a bitter industrial dispute over the miners' pay.

Officially the company says it closed due to the cost of the dispute and security concerns, but privately, insiders also acknowledge that the weakness of the global market also played a role.