These diamonds aren’t forever

A behind the scenes look at one of our rare gem auctions

Last updated: 22 December 2023


We gave the Sunday Times privileged access to one of the world’s most exclusive diamond sales – our inaugural Beyond RareTM Tender: The Art Series in Geneva, Switzerland – to discover how we sell our rare gems.

The sale of our Born of this World collection marks a new chapter for us, showcasing pink and red diamonds from the now-closed Argyle mine in the East Kimberley region of Western Australia, and two Fancy Intense Yellow diamonds from Diavik.

Here is Deputy Business Editor Jon Yeomans’s take on what it’s like to attend a strictly invitation only event, where the bidders – a mixture of jewellers, dealers and buyer’s representatives – are only told the exact location 24 hours beforehand.

Kept under lock and key

“A pair of security guards stood in the corridor outside. The head of security answered the door and kept a watchful eye on the 87 diamonds arrayed in clear glass boxes. Video cameras on tripods monitored the room.

‘We can’t talk about our security arrangements,’ Rio’s PR adviser explained.

“Quite right, too. Just one of the tiny rocks on display could cost $200,000. A set of five, cut in similar shapes and grouped together by Rio’s marketing team, might fetch $750,000. But the showstopper, perhaps, was a red diamond of the deepest intensity — a ‘vivid’, in the language of the trade, which sells for millions of dollars per carat. It was about the size of a sequin.

“If white diamonds send buyers into raptures, coloured diamonds can provoke borderline delirium.

‘It’s a bit of an addiction,’ said John Glajz, managing director of Glajz, a diamond trader based in Singapore, who was in town to bid on the collection.

‘I’m fascinated that nature can do this. It’s a bit of a love affair.’”

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Inspiration from the art world

The Beyond RareTM Tender: The Art Series takes its inspiration from the art world – each polished diamond an extraordinary natural work of art with an esteemed provenance and a captivating story of rarity. Titled Born of this World, the first collection in the series, showcased 87 diamonds, weighing 29.96 carats in total, and included:

  • 7 ‘Masterpieces’ comprising sets of Argyle Pink DiamondsTM and yellow Diavik diamonds, selected for their unique beauty and accompanied by bespoke artwork.
  • A rarified offering of 11 perfectly matched pairs of coloured diamonds.
  • 30 exquisite single diamonds, including one remarkable Fancy Red Argyle diamond.

A pink diamond love affair

“Pink diamonds burst into the public consciousness in 2002, when Ben Affleck gave Jennifer Lopez a six-carat pink rock for an engagement ring, going against the prevailing trend for white diamond rings.

“For the past few decades about 90 per cent of the world’s pink and red diamonds have come from the Argyle deposit, which was discovered in 1979. Rio’s explorers had spent the better part of a decade tracing the mine’s seam before a geologist stumbled on a diamond in a termite hill. As clues go, it was a pretty good one.

“The mine began producing in the mid-1980s and Rio set about cultivating Argyle Pink as a brand name. It was a surprising move for the miner, which is not exactly a luxury powerhouse; it makes most of its money digging up iron ore to sell to China.

“Each year a crop of Argyle pinks are sold in a private tender – but the writing has been on the wall for the brand. By the 2010s the mine was becoming depleted and it closed for good in 2020. The stones on display in Geneva this month represented almost the last batch.

“As Argyle diamonds have become more scarce, prices have jumped, outperforming their white cousins and even many stock markets.”

How do you price a pink diamond?

“The pressure was on, then, in Geneva for buyers to come up with a knockout bid for the remaining diamonds. Under the rules of the tender, bidders have just an hour and a half to view the merchandise, and then they have to decide which stones to bid for and how much, while having no clue what their rivals may pay.

“’It’s subject to a lot of intrigue, a lot of second guessing and a lot of game theory,’ said Patrick Coppens, general sales manager at Rio.

“About 80 bidders have been invited to view the diamonds in Geneva, Belgium and Australia this year. In past tenders, some brave souls have tabled bids for the entire catalogue. Rio spends a day or so crunching the numbers to work out who has won, and then the phone calls go out.”

2 GIA Fancy Vivid Purplish Pink Radiants from the Argyle Diamond Mine, and 1 Fancy Intense Yellow Modified Cushion from the Diavik Diamond Mine. The carefully curated set is 3.83 carats in total
2 GIA Fancy Vivid Purplish Pink Radiants from the Argyle Diamond Mine, and 1 Fancy Intense Yellow Modified Cushion from the Diavik Diamond Mine. The carefully curated set is 3.83 carats in total.

No shortage of buyers

“Rio and its buyers insist there is no shortage of willing customers for these stones. ‘What we know from cars, wines or paintings is that if you buy the best of the best there will always be customers for that, regardless of recessions,’ said Ulrik Hartmann, founder of the Copenhagen-based Hartmanns jewellers, another bidder.

“Once the Argyle supply runs out all the pink diamond trade will be in a second-hand market, which Rio is keen to facilitate by recertifying old diamonds as genuine Argyle products and boosting their resale value.

“Diamonds are still a niche pursuit for Rio: sales in the division hit £800 million last year, paling by comparison with its bulk commodities arm…. Rio’s only other diamond mine is Diavik in Canada, which produces white diamonds and a few rare yellow stones. It, too, is winding down and is slated to close in 2026.”

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The next chapter

Almost the entire world’s supply of rare pink, red, blue and violet diamonds come from our Argyle mine, which ceased production on 3 November 2020.

With 37 years of Argyle pink diamond production in global markets, we continue to manage the Argyle Pink Diamonds™ brand through sales of remaining inventory, secondary market platforms, certification processes and creative collaborations with Argyle Pink Diamonds Icon Partners™ and other renowned national and international jewellers.

Scouting for new mines is getting harder

“Rio is scouting for new prospects in Canada and Angola.

‘Finding new mines is getting harder for sure,’ said Sinead Kaufman, chief executive of its minerals division.

‘And the rarity is something that we can see increasing over time for all natural diamonds.’

“Diamond dealers hope that rarity will support demand even as the market faces stiff competition from synthetic diamonds, which are chemically identical but grown in a lab and cost a good deal less.

“As for what makes a diamond pink, no one is exactly sure. All natural diamonds are forged over millions of years under intense heat and pressure. The present theory is that tectonic shifts in the distant past – say, during the break-up of mega continents – fractured the diamonds’ lattice and created the reddish hue, which only becomes clear when it is cut and polished.”

Reds and pinks are cut to sparkle

“But just what are pink diamonds like up close? Under the lens of a diamond dealer’s loupe, the intricate cuts of each stone are perfectly clear. Small shards of red and pink flash like spotlights out of the gem. From a distance, they sparkle only fitfully. And the Argyle diamonds in this latest batch are really very small.

“It is enough to keep buyers such as Jody Wainwright, director of the family-owned jeweller Boodles hooked.

‘How do you price a pink diamond?’ he asked. It was a problem he was shortly to face, as he sat down in the Geneva hotel room with pen and paper to do his sums.

‘It’s more like pricing a work of art.’”

6 ethereal Fancy Vivid Purplish Pink and Purple-Pink Pears from the Beyond Rare™ Tender: The Art Series Born of this World collection
6 ethereal Fancy Vivid Purplish Pink and Purple-Pink Pears from the Beyond Rare™ Tender: The Art Series Born of this World collection.

Exceptional results

The Beyond Rare™ Tender: The Art Series delivered an exceptional result, reflecting the collection’s rarity and careful curation. Bidding was strong, with individual, multiple and global bids and a broad geographic spread of successful bidders from Australia, Europe, Japan, Hong Kong, Singapore, US and Israel.

We are delighted with the results from this new sale format for Rio Tinto’s diamonds business, delivering results that reflect the global demand for highly collectible natural coloured diamonds and the resulting value creation.

- Sinead Kaufman, Chief Executive Minerals

The only Fancy Red diamond in the collection was won by Kununurra-based bespoke jeweller, Kimberley Fine Diamonds.

I am delighted that this exceptional gem will stay in Australia, entrusted with Kimberley Fine Diamonds to continue its onward journey as one of the few highly coveted Fancy Red diamonds produced from the Argyle Diamond Mine. It is an extraordinary diamond of esteemed provenance, with a beauty that reflects its magnificent birthplace here in the East Kimberley region of Western Australia.

- Frauke Bolten-Boshammer, Owner Kimberley Fine Diamonds

The Japanese market also showed intense interest – Argyle pink diamonds have long been revered by Japanese jewellery designers. Distinguished jeweller Gimel, representing the ultimate in bespoke Japanese craftsmanship, was a successful bidder in The Art Series. Gimel has been creating beautiful hand-crafted Argyle pink diamond pieces for the past 25 years, crafted from an atelier carved into a mountainside near Japan’s Setouchi National Park.

We have a long relationship with the beautiful and rare Argyle pink diamonds and we are looking forward to transforming our successful bids into works of art, to be treasured for future generations.”

- Frauke Bolten-Boshammer, Owner Kimberley Fine Diamonds

Longstanding Argyle Pink Diamonds Authorised Partner™, Kunming International Ltd, was another successful bidder.

We see strong ongoing market demand for the truly rare – irreplaceable fancy-coloured natural diamonds with impeccable provenance. These diamonds are in a league of their own and will consistently transcend the fluctuations of economic cycles.”

- Harsh Maheshwari, Executive Director, Kunming International Ltd

Our diamond operations

In addition to owning the Argyle Pink Diamonds™ brand, we own and operate the Diavik Diamond Mine in the Northwest Territories of Canada, and we continue exploration in Canada. And in Africa, we have signed an exploration joint venture agreement with Endiama, the national diamond mining company of Angola, to evaluate the Chiri kimberlite in the Lunda Sul Province of Angola.

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