market soars for finest remaining Argyle diamonds

Four years after Rio Tinto closed its Argyle diamond mine in remote Western Australia, the Anglo-Australian group is attempting to stimulate the eponymous brand, which it has no plans to relinquish despite its dwindling inventory.

“Argyle pink tender diamonds have outperformed all major equity markets over the past two decades, achieving double-digit price growth in that time,” points out Patrick Coppens, general manager for sales and marketing at Rio Tinto Diamonds.

Indeed, just one carat can now sell for millions of dollars. Diamond jewellery house Graff paid a record $4.2mn at a Phillips Geneva auction in May for the Argyle Phoenix, a rare 1.56 carat red diamond.

During its 37 years as the world’s only consistent source of pink diamonds, the Argyle mine produced more than 865mn carats of rough diamonds in total, of which just 0.1 per cent were classified as pink, including even rarer red, blue and violet diamonds.

Previously, pink diamonds were found only sporadically, mainly in Africa or Brazil, and were generally lighter in tone than Argyle’s distinctive pulsating candy-pink hues — a colour never seen before, and an intense saturation combined with spectacular brilliance. Throughout the mine’s life, Argyle Pink became an object of desire as well as an asset class, its value appreciating due to extreme rarity and exclusivity.

Rio Tinto managed the supply chain through an invitation-only, sealed-bid tender process. As designers explored Argyle’s unique palette of colour and light, the coloured diamond was transformed from a gemmological curiosity into a focal point of high jewellery.

At the time of the mine’s closure, there was much conjecture over the future of the brand, as well as how the value of the diamonds themselves would change, now that supply was finite. In 2023, Tiffany & Co — under its LVMH ownership — purchased a collection of 35 diamonds unearthed in the last stages of the mine’s life and curated by Argyle, both to showcase the full range of colours and mark this milestone in diamond history.

In the end, Rio Tinto made the decision to hold on to the brand and continue its custodianship, while also managing the secondary market, through initiatives such as a concierge trade-only trading platform, a recertification and reauthentication scheme, and a new-style Beyond Rare Tender sales event, incorporating what Argyle calls Old Masters — “hero” stones from past yields, that have been held in collections and vaults. For Rio Tinto, this offers an alternative sales platform to the auction houses.

The new format for the Tender sales event showcases the finest specimens from the remaining — but dwindling — inventory from the mine, alongside selected historic stones from past Tender collections. It also includes significant white and yellow diamonds from the Rio Tinto-owned Diavik mine in the Northwest Territories of Canada, scheduled to close in 2026.

The 2024 Beyond Rare collection is titled Colour Awakened and is the second in its Art Series, launched last year. The theme presents the perfectly cut and polished diamond as a work of art. “Historically, the prices of Argyle Pink diamonds have been more closely aligned with the rare art and collectible markets than with those of white diamonds,” notes Coppens.

Colour Awakened offers 48 lots, comprising 76 stones, including pink and violet diamonds and one fancy purplish red diamond, as well as nine curated sets, two of which feature a 2.47 fancy intense yellow diamond and a 4.04 carat D colour, respectively, both from Diavik.

The highlight, however, is the hand-chosen group of seven Old Masters, unearthed 10 or more years ago, all round brilliant cuts, including one red diamond. The earliest of these emerged in 1987, says Michelle Sherring, Rio Tinto diamond sales and development manager, when prices per carat were in the tens of thousands of dollars, whereas today they have climbed to multimillions, as evidenced by the Argyle Phoenix at $2.7mn per carat.

François Graff, the chief executive behind Graff’s acquisition of the 1.56 carat red diamond at auction, describes the stone as “incomparably rare and extraordinarily beautiful; one of the finest examples of a Fancy Red diamond that we have ever encountered”.

Graff says demand for pink diamonds continues to grow, particularly among Asian clients. “With the closure of the Argyle diamond mine, we have seen a continued appreciation in the value of these stones,” he observes. “Currently, there are very few sources of pink diamonds in the world, which has only served to heighten both their rarity and desirability.”

Scott West, of New York coloured diamond merchants LJ West, likens the Argyle Pink diamond to a “modern antiquity”, stressing the extreme rarity of the stones, and the “perfect storm” conditions under which they were formed 1.6bn years ago. Now, he suggests, in today’s “soft” economic climate, is the time to buy, “if you have the stomach for it”.

Retail jewellers John Glajz in Singapore and John Calleija in Sydney, both Argyle specialists, are the two of the so-called “icon” partners appointed after the mine’s closure to create special edition jewels, objects and coins set with Argyle Pink diamonds.

Glajz says that, in today’s global market slowdown, in which white diamonds have been commoditised, Argyle stones are “holding” well.

As a partner, he has access to stones that “came through the Argyle system after the mine closed”. And although, according to Sherring, remaining inventory from the mine is a “mere teaspoonful”, possibly only enough for one more Tender collection, Glajz says that, after 30 years of involvement, he is still committed to Argyle Pink diamonds. “There’s always something at the back of the safe.”

Rio Tinto is now in the middle of a lengthy and complex process to restore the site of the mine to as near its original state as possible. This regeneration project, in consultation with the indigenous aboriginal owners, is scheduled to be completed in 2026, and has already involved a reported A$850mn ($560mn) in costs.