The diamond was recovered by Lucapa Diamond Company and its Lulo partners Empresa Nacional de Diamantes (Endiama) and Rosas & Petalas, in March and sold into a cutting and polishing partnership with Safdico International.

It is the largest gem-quality coloured rough diamond to be recovered from Lulo to date.

The cutting and polishing of the pink diamond delivered three polished diamonds: a 15.2 carat heart-shaped diamond and two pear-shaped diamonds weighing 3.3 carats and 2.3 carats.

The heart-shaped diamond was graded by the Gemmological Institute of America as Fancy Intense Orangy Pink, with a clarity grade of VVS1 and excellent gradings for both polish and symmetry.

Under the partnership with Safdico, the Lulo partners retain a share in the margin to be generated from the sale of polished diamonds.

The Angolan government brought in new marketing regulations last year, allowing miners the ability to sell diamonds into other value-accretive channels and partnerships to attract additional value over mine gate sales.

"The recent enactment of the Angolan diamond marketing regulations is having the desired effect," Lucapa managing director Stephen Wetherall said.

"Pink coloured diamonds are rare and constitute less than 0.1% of global diamond production.

"With the recent closure of the renowned Argyle underground mine in Australia, which produced about 90% of the world's natural pink diamonds, these diamonds are about to become even more scarce.

"This bodes well for the sale of the 15.2 carat polished pink diamond and other diamonds derived from this unique value accretive polishing partnership."

Earlier this week, Lucapa and its partners received US$6.6 million from the sale of 4269 carats of diamonds from Lulo, representing an average price of $1550 per carat.

Year-to-date sales reached $28 million from the sale of 20,397 carats at $1371 per carat.

Lucapa shares were 1.8% lower at A5.4c, valuing the company at $43.5 million.