Behind the scenes at the Argyle Pink Diamond tender

The Argyle Pink Diamond tender happens just once a year, with the locations kept secret, the security high and the 150 bidders carefully vetted. The Argyle Mine owned by Rio Tinto produces 90% of the world’s pink diamonds, but so rare are these stones that a year’s worth of shifting tonnes of earth can be held in a cupped hand, which explains why these stones can sell for over $1 million dollars a carat.

How pink diamonds are formed is an intriguing question that is still being studied. All diamonds were formed under pressure, but nowhere was the pressure greater than in the Argyle pink diamond pipe, where it caused the crystal lattice of the diamonds to compact and twist. This means that light travelling through the stone is bent at a wavelength associated with the far end of the colour spectrum, creating hues of pink, and even red and violet. Unlike yellow diamonds, which have traces of nitrogen, or blue diamonds that have boron, in pink diamonds the colour is unrelated to trace elements – it is all about the way the crystal is structured.

Read more about the history of pink diamonds.

Pink and red diamonds are rarely over two carats, meaning an entire year’s yield can fit in an ashtray.

Walking in the hushed tender room, the 63 stones that make up this year’s Chroma collection are neatly lined up in black plastic boxes with acrylic tops. Each diamond rests on a white cushion visible through the top of the boxes and, closely watched by several security guards, what first strikes me is, well, how small they are, so small that they are handled with tweezers. This is because it is extremely unusual to find a top-quality pink diamond of over 1 carat. Josephine Johnson, Manager of Argyle, explains: “To put it into perspective, retailers will often call us asking if we have a 1 carat, round pink diamond and we have to say no. We are lucky to produce 10 1 carat brilliants a year, and there are only three in this year’s production. In fact, less than five a year is the average, so a 1 carat pink diamond engagement ring would in fact be a one-in-a-million gift.”

Billed as the most exclusive diamond sale in the world, the Argyle Pink Diamond tender is strictly by invitation only, with bidders arriving for a two-hour viewing armed with nothing more than a loupe and a cool head. With approximately two minutes to view each diamond, pencil in hand, the diamantaires and jewellers enter their bids into the secret tender and wait to hear if their offer has been successful. With only 63 stones between over 100 bidders, it is rare for any one jeweller to take home more than one or two.

The day I visited, Jody Wainwright, gemmologist at Boodles, the British jeweller, was inspecting the stones and making his bids. This is the first time that Boodles has been invited to bid, and Wainwright shared his insight into why the Argyle Viva has caught his eye. He is hoping to buy eight of the stones.

Watch our video of Jody Wainwright at the tender admiring the “bubblegum pink” Argyle Viva diamond:

In the grand scheme of gems, pink diamonds are relative newcomers. Though formed over a billion years ago, until the discovery in the 1970s of the Argyle mine in the north of Western Australia, these diamonds were a sporadic find and, though admired, their value or origin remained something of a mystery. These pink wonders were such a novelty that they were almost exclusively the property of royalty and usually set in tiaras or turbans. After a 10-year search in the vast landscape of the north of Western Australia, the Argyle mine dramatically changed the pink diamond scene. Since then the mine is close to depletion and, seeking to extend its life, in 2014 the operations moved underground. Today, 45 kilometres of underground tunnels are home to a mini city complete with traffic lights, workshops and canteens with staff working around the clock, 365 days a year, to bring these diamonds to light. Though this is only the 32nd year of production, the experts say that by 2021 no more pink diamonds will emerge from Argyle, only adding to the rosy gem’s desirability.


The five heroes of the Argyle Diamond Tender 2016 include two very rare violets as well as two purple pinks and a red diamond.

This year, for the first time, all the diamonds are entirely from the new underground source. And it is a bumper crop, as Johnson explains: “The Chroma collection is the finest we have presented in 32 years, with diamonds that are larger, more potent in colour and higher in clarity, so on all counts a superb result.” The five most impressive stones, including two rare violet diamonds, have been given names this year – the Argyle Violet, Argyle Ultra, Argyle Viva, Argyle Thea and Argyle Aria. Josephine Johnson, Manager of Argyle Diamonds, talks us through these remarkable diamonds in our video below.
Undoubtedly the star of the show is the Argyle Violet, below. Johnson says of this stone: “We have only found 20 violet diamonds in the last 32 years, and they all add up to 12 carats, so to have a 2.83 carat violet is exceptional. It is the largest violet ever to come from our mine, and it was cut from a 9.17 carat rough.”

Argyle prides itself on the fact that it has complete custody of these diamonds from mine to sale to the final retailer, as each stone is cut and polished in house. Johnson, who oversees the entire process, remarks: “The rough looks like slices of Turkish Delight and polishing almost seems like a crime, but it does bring out their brilliance and colour.” Where these stones will end up remains to be seen, but if past years are anything to go by, none will be left on the table.


A close-up of the remarkable Argyle Violet, a 2.83 carat oval Fancy Deep Grayish Blue Violet diamond as graded by the GIA.