Ratanlal Prajapati and his three partners unearthed the precious stone on leased land in Madhya Pradesh's Pana district.
It was deposited at a local diamond office on Monday and will be auctioned on 21 September.
Local experts believe the diamond could be worth up to â¹40 lakh (£40,000)
Government royalties and taxes will be deducted from the value of the diamond before the four workers get their share.
Raghuvir Prajapati, one of the group, said he and the others had been mining for 15 years without much luck until this month.
“We leased small mines in different areas for the past 15 years, but did not find any diamond,” he told reporters.
“This year, we have been mining on a leased land at Hirapur Tapariyan for the past six months and were pleasantly surprised to find a diamond weighing 8.22 carat,” he said.
He said he and his partners will use the proceeds from their diamond find to provide a better life for their children.
Panna district, located about 380 km from Bhopal, has diamond reserves estimated at 12 lakh carats, officials said.
The workers' find will be auctioned along with 139 other diamonds later this month, they added.
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