Mine shows high amount of rare stones, says Star Diamond

By Susan McNeil

Samples taken from the diamond drilling site at Fort a la Corne show an “exceptionally high proportion of Type IIa diamonds” says Star Diamond, the Saskatoon company collecting the samples.

Star Diamond is working with Rio Tinto, a large trans-national company to see if the Fort a la Corne area is a viable diamond mine.

George Read, a senior technical advisor to Star Diamond, sounded positive in a news release issued yesterday.

“The presence of high-value diamond groups (Type IIa) greatly strengthens the future potential diamond pricing from the Star Kimberlite,” he said.

Diamonds are split into Type I and Type II classes with sub classes of a and b assigned, based on levels of impurities.

Type IIa are almost devoid of impurities and have the highest amount of thermal conductivity. They make up between one and two per cent of all natural diamonds. They are considered the most chemically pure diamond.

The only type of diamond rarer is Type IIb, which is also very valuable.

According to the news release, finding the Type IIa diamond increase the odds the mine will go ahead, although no decision has been made yet.

“The presence of a significant proportion of Type IIa diamonds recovered in the Star Kimberlite by the Trench Cutter greatly increases the potential for the recovery of large (plus 100 carat), high-value diamonds from a future mine. Analysis of the trench cutter diamond parcels indicate a significant proportion of Type IIa diamonds, many of which are top white in colour with high value,” said Read.

The release makes a point of noting the “exceptionally high proportion of Type IIa diamonds in the larger size fractions of the EJF of which 53 per cent (8 of the 15) of the largest stones, 4 carats and above are Type IIa.”

EJF refers to the geological unit the diamond was taken from and the largest Type IIa diamond identified was a 16.96 carat stone valued at over $110,000 (USD).

Test drilling has been going on for some years with 2019 seeing ten bulk samples collected.

In the world only a few mines regularly produce Type IIa diamonds, with the Letseng Mine in Lesotho and Karowe in Botswana the top two.