Petra Diamonds’s first quarter revenue jumped 55 per cent, boosted by the sale of a 122 carat blue diamond.
Revenue jumped to $100.8m (£62.1m) in the first quarter, up from $65.1m for quarter one last year.
Petra sold an 85 per cent interest in the rare diamond for $23.5m back in September.
The revenue gain was also boosted by a two per cent increase in production, which rose to 833,744 carats, from 816,735 carats in the same period a year earlier.
The company said that the market was experiencing the customary seasonal softness but that it was not changing its price expectations for the coming year.
The next quarter is likely to provide good news for Petra: another huge diamond, this one a 232 carat Cullinan white diamond, sold for $15.2m on 24 October 2014, and will be included in quarter two results.