MIRNY, RUSSIA-Diamonds are forever, and so is the permanently frozen ground of Yakutia in north eastern Siberia, home to huge diamond deposits that ensure Russia’s supremacy in world production of the luxury stone.

In the city of Mirny, the sun shines almost continuously during the region’s white night season in early July, with temperatures exceeding 30 degrees Celsius.

But the summer does not last long. Yakutia is known for having the coldest winters on the planet, which drag on for nine dark months.

This region - rich in oil, gas and precious metals - is also home to eleven out of twelve mines belonging to Russia’s Alrosa group, the world’s largest producer of rough carats.

The majority state- and local government-owned company employs most of Mirny’s 35,000 inhabitants and contributes around 40 percent of the wider region’s budget in taxes.

Alrosa, which has been criticised by some locals for alleged environmental damage including polluting water supplies, has a reputation for secrecy but is now making efforts to demonstrate some of its work.

In Mirny, a gaping hole of massive depths -- the abandoned mine “Mir” -- stretches out into the city. It is more than a kilometre in diameter and 525 meters deep, or nearly two Eiffel towers placed end to end. Oleg Popov, the director of Mirny’s diamond sorting centre, shows off a billiard table covered in shiny stones.