Gaborone: Lucara Diamond Corporation has recovered rough diamonds weighing more than 1 carat apiece – including one weighing 4.56 carats – from an ore sample that came from its BK02 exploration project in Botswana.

That largest stone was a white-grey octahedron, the miner said on Monday. In total, the company recovered 22 diamonds of more than a carat each, including two stones that exceeded 2 carats.

The combined weight of all the diamonds recovered from the 5,021-tonne sample was 309.79 carats, at a sample grade of 6.2 carats per 100 tonnes of ore.

Together with an earlier sample from BK02, Lucara has recovered a total of 584.12 carats from 10,937 tonnes of kimberlite at a sample grade of 5.3 carats per hundred tonnes. The three largest diamonds from the two samples weighed 5.48 carats, 4.56 carats and 2.71 carats respectively.

The diamonds from the test are due to be valued independently early in the second quarter of 2017. Lucara’s chief executive officer, William Lamb, described the results as “very encouraging.”