A professional examination report of the massive 391-carat diamond recovered by Meya Mining in Sierra Leone suggests the diamond contains metallic inclusions, mainly iron-rich metals.

 This means it formed deep in the Earth between 360 and 750 kilometres below the surface. 

Trustco Group Holdings holds a 19.5% interest in Meya Mining, which operates under a 25-year exclusive diamond mining license in Sierra Leone’s Kono District. 

Trustco states that the professional examination report, conducted by Evan M. Smith of the Gemological Institute of America (GIA), confirmed the diamond as Type IIa, which is a classification that indicates high purity due to the absence of nitrogen. 

Trustco added that further analysis showed the diamond is part of the CLIPPIR (Cullinan-like, large, inclusion-poor, pure, irregular and resorbed) variety, similar to some of the world’s most valuable diamonds. 

“Despite these inclusions, large parts of the stone remain clear, making it an important geological find. The discovery of this CLIPPIR diamond at the Meya mine confirms that the area contains large Type IIa diamonds,” reads a Trustco statement. 

The 391.47-carat diamond was part of a 515-carat rough diamond recovered in the Meya River kimberlite domain in August 2024 in the first of 16 domains targeted by Meya. 

Along with two smaller fragments weighing 105.43 and 18.11 carats, this marks the second significant find from the region, confirming its potential as a source of high-value diamonds. 

Quinton Z van Rooyen, deputy CEO of Trustco, said “The recovery of this CLIPPIR diamond sheds light on Meya’s extraordinary geological landscape. As the diamond world contemplates the eventuality of a 5000-carat stone, our recent find indicates that Meya’s unique geology positions us well for potentially historic discoveries in the future”.

Trustco’s statement continued that Meya Mining is now focused on improving its recovery process to prevent breakages of large diamonds in the future. 

“The company is working with its engineering and processing partners to upgrade the plant and increase its capacity to recover large diamonds intact. This discovery strengthens Trustco’s Mining portfolio but also highlights Sierra Leone’s position as a key player in the global diamond market,” reads the statement.