A recent bulk sample from the Star diamond project, in Saskatchewan, suggests that the deposit has the potential to produce large, high-value diamonds like the ones recovered from Gem Diamonds' Letseng mine, in Lesotho, according to Canadian junior Shore Gold, miningweekly reported.

More than a quarter of the diamonds bigger than 2,7 ct from an underground bulk sample were Type IIa diamonds, which are particularly rare and are estimated to account for less than 2% of all natural rough diamonds in the world, the company said, according to the report.

The most prolific source of Type IIa diamonds is Letseng, and Shore has conducted a study which suggests that the Star project may have a similar proportion of these rare stones to Letseng.

Many high-value, top colour, large specials are Type IIa diamonds, which include all of the ten largest known rough diamonds recovered worldwide, from the 726 ct Jonker to the 3 106 ct Cullinan, Shore said.

"The presence of a significant proportion of Type IIa diamonds greatly increases the potential for the recovery of large (plus 100 carat), high-value diamonds at Star,” commented Shore senior vice-president for exploration and development George Read.

“Study of the Star diamond evaluation parcel shows that it contains both top white octahedral diamonds (Type Ia) and a significant proportion of Type IIa diamonds, some of which are top white in colour.

“The presence of these two high-value diamond groups (octahedra and Type IIa) greatly strengthens the future potential production diamond pricing at Star."

Shore Gold recently completed a prefeasibility study on its diamond project in central Saskatchewan, which would be the province's first diamond mine, said the report.