The group, which owns the Kareevlei Diamond Mine in South Africa, also saw operating losses reduced 64% year-on-year to £538,000.
During the period, overall carats produced at the mine jumped 79% when compared to the six months ended 30 June 2020, reaching 8,949.
Moreover, BlueRock saw a 40% year-on-year spike in the sales price per carat of $436 (£319).
Mike Houston, executive chairman at the group, said: “The first half of the year has been a challenging one and despite the delays in the expansion project, good progress has been made on a number of fronts.
“The market rebounded in early 2021 with excellent prices achieved throughout the period and there is a very positive outlook for the remainder of 2021.”
Looking ahead, Houston highlighted the discovery of “several large stones” that has “further confirmed the potential” of BlueRock’s Kareevlei operation.