Gem Diamonds has sold its 357 carat diamond for US$19.3 million.
The massive stone was uncovered at the Letšeng mine, in July earlier this year.
"The Letšeng mine has produced two remarkable +300 carat diamonds during the year to date,” Gem Diamonds CEO Clifford Elphick said.
These discoveries came after the uncovering of two 160 carat plus diamonds at the operation in January.
“The 314 carat diamond, which was recovered in May 2015 and sold into a partnership arrangement in June 2015, and the 357 carat diamond which was sold on tender in September 2015 for US$19.3 million, “Elphick stated.
“Both of these diamonds achieved top prices despite current market conditions, providing further evidence of the price resilience of Letšeng's large top quality diamonds."
The diamond market is currently experiencing a slow down similar to the rest of the resources industry, after strong predictions of rapid growth in 2014.
Earlier this year De Beers forecast a challenging market for rough diamonds; a consensus seemingly held by the rest of the market as well, while IBISWorld slated an annual four per cent decline in the industry from 2011 through to 2016.
This weaker market consenus was demonstrated by the formation of a new global diamond consortium in May, focused on “the development of the sector”.
The newly named Diamond Producers Association (DPA) brings together ALROSA, Rio Tinto, De Beers, Lucara Diamond Corp, Petra Diamonds, Gem Diamonds, and Dominion Diamond Corp.
Housed in London, the DPA is focused on driving consumer demand in the sector, “including joint category marketing initiatives; providing a reliable source of industry information, including trade and consumer research; acting as the unified voice of the diamond producers, when required and/or appropriate, with industry and non-industry forums/organisations; communicating the role and contribution of diamond producers to the diamond sector and broader society; and sharing best practices in health and safety, license to operate, supply chain integrity and environment management”.
The DPA will focus on the commissioning of research to build a targeted activity plan for the coming three years.