Seven poor labourers in Panna, a diamond mining area in central India, have made a discovery that they say has the potential to change their lives forever.

The delighted men said they found a large diamond on a plot of land they had leased two years back.

On the weighing scale, the rock measured 17.96 carats and Panna diamond official Ravi Patel said it was "gem quality" - one of the finest varieties of natural diamonds that exist.

Describing the diamond as "precious", Patel said it would be put up for auction in the first half of October. He estimated its worth to be at least 5m rupees ($52,400; £38,800).

Diamond finds are not so rare in Panna, which is in Madhya Pradesh state - home to most of India's diamond reserves.

The district is among India's least developed and its residents face poverty, water scarcity and unemployment.

With few job opportunities in the city, residents hope for a prized find to improve their fortunes and the region remains a prime destination for diamond hunters.

But finders are not always keepers.

Reports say a majority of Panna's miners are daily-wage labourers who work for lease-holders - if they find a diamond, the money goes to the lease-holder and not the miners themselves.

But the latest find is one of the few cases where the actual finders would benefit.

The mine in Panna's Sarokha village was leased for a meagre sum by Akhilesh Pal and six others two years back, Press Trust of India reported.

Pal said the mine had been shut for a year and was opened only recently. On Monday, as he inspected the mine after heavy rains, he spotted the rock.

"We had been mining there for about two years," he said, "but we had no luck, so we closed the mine for a year. We had started another mine right next to it."

"When we went there to inspect the new one, we also looked inside the old mine, and that's where we found it - right on top," he added.

Patel said the diamond would be put up for sale at the next quarterly auction due in October when buyers from India and abroad would be able to bid for it.

Reports said the government would deduct a 12% royalty from the sale proceeds and the remaining money would be divided equally among the seven workers.

For some of the poor labourers, the find is set to change the course of their lives - local media reports quoted three of them as saying they were too poor to get married so far and this windfall would now help them find brides.