Russian diamond mining giant Alrosa has recovered a 78.02-carat diamond from its Mir kimberlite pipe.
The miner, which produces a quarter of global output, said in a statement that the diamond measures 28.5mm by 28.4mm by 24.2mm.
The stone has some small inclusions, and is transparent with yellowish and greenish hues, the firm said.
Alrosa analysts at its Diamond Sorting Center estimate the auction value of the diamond at in excess of $600,000.