Tonnage for the quarter rose 12% from the March 2018 quarter to 42,409 tonnes, with 1,847 carats sold, up 18% on the year.
CEO Adam Waugh said the volumes had reached the higher end of expectations, despite an eight-day suspension in February.
The average grade achieved was 3.41 carats per hundred tonnes, 4% higher than the 2018 average, which Waugh said reflected the high quality of Kareevlei's diamonds.
BlueRock also achieved a higher average price of US$371 per carat, a 10% increase on 2018's average.
Two large stones were recovered during the three-month period; an 8.7ct diamond sold for $74,513 and a 16.28ct diamond sold for $78,947.
The company started seven days a week operation on March 26, which Waugh said was starting to show results.
"We have further work to do in improving our operations," he said.
BlueRock's shares rose 5.53% Tuesday to 0.25p (US0.33c) per share, but two thirds lower than the 0.75p/share seen six months ago.