The auction of over 260 diamonds weighing 316.33 carats with an estimated value of Rs 3 crore found in mines in Madhya Pradesh's Panna district began on Tuesday, an official said.
These include an 18.13 carat diamond which had gone unsold on two previous auctions, the official added.
"A total of 261 diamonds weighing 316.33 carats will be auctioned, the process for which began today. The auction will continue for the next two days. The cumulative cost of these diamonds is Rs 3 crore," said Panna Diamond Officer RK Pandey.
He said diamond traders from Gujarat and Mumbai are expected to attend the auction.
Panna district, some 385 kilometres from state capital Bhopal, is estimated to have diamond reserves totalling 12 lakh carats, officials said.
A carat is a unit of mass equalling 200 milligrams and is used for measuring diamonds and other such gems.