RAPAPORT... Star Diamond Corporation's Canadian mining project contains a "significant" proportion of high-value, type IIa rough, according to a study the company performed.The Star-Orion South site in Saskatchewan, which the company owns in partnership with Rio Tinto, holds an "unusually high" number of these stones in multiple units within the mining area, Star Diamond said Monday. In one portion of the site, 52% of the diamonds the company found were type IIa, while another unit comprised 45% such stones.Valuations the company carried out on the rough showed an estimated average price of $2,420 to $4,051 per carat for rough ranging between 2.84 and 7.90 carats."The presence of a significant proportion of type IIa diamonds in the Orion North and Taurus kimberlites greatly increases the potential for the recovery of large (100-plus-carat), high-value diamonds," said Star Diamond senior technical adviser George Reed. "Analysis of the...diamond parcels indicated a significant proportion of type IIa diamonds, some of which are top white in color...and exhibit high diamond prices. Their presence...greatly strengthens the future potential diamond pricing from [those] kimberlites."In total, the Orion North and Taurus units contain between 46 million and 79 million carats of diamonds, Star Diamond added.Image: Rough diamonds from the Star-Orion South project. (Star Diamond Corporation)