The 28.84-carat stone has been named Argyle Octavia after its octahedral shape, and is thought to be one of the most unique large white diamonds to come from the mine.
Argyle, which is owned by Rio Tinto and has been operating since 1983, is best known as one of the world’s premier sources of natural colour diamonds. In particular, it accounts for more than 90 per cent of the global supply of pink diamonds.
Gem-quality white diamonds above 20 carats have accounted for just 0.0007 per cent of Argyle’s production since the mine opened, making the Octavia an ultra-rare find. It’s particularly special as Argyle is set to close in 2020.
Arnaud Soirat, chief executive of Rio Tinto’s copper and diamonds portfolio, said in a press release: “We are delighted with this discovery, which is a testament to the extraordinary Argyle orebody that continues to deliver these miracles of nature, even as it nears the end of mine life.”
The Octavia will be sold by tender in Antwerp later this year.