A number of the alluvial diamonds recovered from stream bulk sampling at Lulo, Angola, are Type IIa - exceptionally rare and pure.
The ASX-listed Lucapa Diamond Company last week reported it had found 45 diamonds of up to 3.75 carats from hard-rock kimberlite sources in the Canguige tributary.
It says follow-up analysis has now confirmed the presence of the Type IIa gems, along with a light fancy yellow. They'll be sent to Antwerp for more detailed analysis.
Type IIa diamonds are exceptionally pure because they have virtually no nitrogen atoms in their crystal structure.
Lucapa is drilling at five prospective pipes and two other priority targets in the Canguige catchment.