Rio Tinto said it was delighted with the results of its first Beyond Rare Tender of polished pink and red diamonds from Argyle, in Australia, and yellow stones from Diavik, Canada, though it declined to reveal any prices.
Sinead Kaufman, chief executive of Rio Tinto Minerals, said only that the results reflected the global demand for highly collectible natural colored diamonds.
The first in a series of sales featured a collection of 87 diamonds, weighing 29.96 carats in total. Successful bidders came from Australia, Europe, Japan, Hong Kong, Singapore, US and Israel.
Among the lots were seven Masterpiece sets of Argyle dink diamonds and yellow Diavik diamonds, 11 matched pairs of colored diamonds and 30 single diamonds, including one remarkable fancy red Argyle diamonds.
The iconic Argyle mine closed in November 2020 after 37 years. It produced 90 per cent of the world’s pink, red, blue and violet diamonds.
Rio Tinto has launched the Beyond Rare Tender, an inaugural collection of 48 lots of polished fancy-colored diamonds.
The miner will offer 87 diamonds in total, including its legacy inventory of pink and red stones from the shuttered Argyle diamond mine in Australia and yellow diamonds from its Diavik site in Canada, it said on Tuesday.
The new collection is “a testimony to the ongoing demand for highly collectible natural diamonds,” said Sinead Kaufman, chief executive of Rio Tinto Minerals. “This carefully curated collection of rare jewels will be in strong demand by the world’s finest jewelers, collectors and diamond connoisseurs.”
Titled The Art Series, the invitation-only tender is inspired by the art world, the company said. The combined weight of the diamonds is 29.96 carats.
They include the following:
Seven diamonds consisting of Argyle pink stones and yellow Diavik ones, which the company says will be accompanied by bespoke artwork.
An offering of 11 matched pairs of colored diamonds.
Thirty single diamonds, including one distinctive fancy-red Argyle diamond.
The closure of the Argyle mine in Australia and the continued strong demand for exceptional fancy pink and red diamonds means the market for Argyle pink and red diamonds “have never been stronger,” said Patrick Coppens, general manager of sales and marketing for Rio Tinto’s diamonds business.
The 48 lots will be shown in Australia, Switzerland and Belgium, with bids closing on November 20.
Western Australia’s Argyle mine was among nature’s preeminent treasure troves for nearly 40 years. At its peak, Argyle produced more coloured diamonds than anywhere else on Earth and earned an especially sparkling reputation for its unparalleled cache of pink diamonds.
Researchers have spent decades trying to unravel the origins of Argyle’s glimmering gems. Now, by dating minerals in the mine’s volcanic rock, scientists think they may have finally pieced together the process that created the deposit around 1.3 billion years ago. In a paper published on Tuesday in Nature Communications, the team posits that the breakup of an early supercontinent lifted Argyle’s salmon-coloured stones from crushing depths toward Earth’s surface.
Located 2,200 kilometers northeast of Perth, Australia, in the country’s rugged Kimberley region, Argyle mine once covered an area the size of 94 football fields. Between its opening in 1983 and closure in 2020, when mining the gems there was no longer economically viable, Argyle produced more than 865 million carats of rough diamonds. Most of these stones come in pale shades of yellow or brown. But a small percentage of the site’s diamonds radiate rich pinks, purples or reds. More than 90 percent of the world’s pink diamond supply including the nearly 13 carat Pink Jubilee has come from Argyle.
The pink hue of Argyle’s most lavish diamonds is linked to damage they underwent deep within the earth. According to Hugo Olierook, a geologist at Curtin University in Perth and lead author of the new study, these diamonds start out colourless. But immense tectonic pressure from colliding continents can alter the stones’ crystal structure, unlocking the potential colours hidden within. “The diamonds are being forced to bend and twist,” Olierook says. “If they’re twisted just a little bit, it will turn some of these diamonds pink.” Further twisting makes them become brown.
Argyle’s diamonds took on their pink and brown tints around 1.8 billion years ago, when a piece of what is now western Australia smashed into the northern Australian plate and warped the region’s rock. But this only explains part of Argyle’s origin story. When the continents collided, the area’s diamonds were buried in the mantle, hundreds of kilometers below Earth’s surface. If the crystals had been closer to the surface, their carbon atoms would have been compressed into a different structure, transforming them from shimmering diamonds to lumps of dark gray graphite.
A volcano was necessary to bring the molten diamonds up from our planet’s mantle. “You need some sort of tectonic trigger to bring them up to the surface,” Olierook says. As the melt rises, carbon dioxide and steam expand, sparking an eruption that he compares to popping a champagne cork. At Argyle, this eruption likely occurred at a beach, where sand and seawater interacted with volcanic rock called lamproite.
To determine when the eruption occurred, the team sliced two thin sections of Argyle’s volcanic rock and polished them down to a minuscule width. Analyzing the sample’s mineral makeup under a microscope, the researchers were able to pinpoint sand grains from Argyle’s ancient beach and to date them with the help of radioactive elements they contained. By dating the youngest sand grains, the scientists were able to estimate when the beach was buried in lava. They also used tiny lasers to determine the ages of titanite minerals, which formed in the rock when the magma melded with quartz in the beach sand.
Comparing the ages of the youngest sand grains and the oldest titanite crystals allowed the researchers to estimate that the eruption at Argyle occurred between 1.3 billion and 1.26 billion years ago. This age range was older than previous estimates, which surprised Olierook and his colleagues. “We had a betting pool going, and nobody got 1,300 million years,” he says. “That was one of those glass shattering moments.”
That eruption timing corresponds to a volatile period in Earth’s tectonic history when one of the first supercontinents, called Nuna, was splintering apart. The team posits that this instability may have reopened a seam along the continental boundary where Argyle is now situated. This in turn sparked the volcanic activity that brought the diamond-bearing melt toward the surface, creating Argyle’s expansive diamond deposits.
The new time estimates add crucial context for understanding the volcanic eruption at Argyle, says Evan Smith, a researcher at the Gemological Institute of America, who researches the geology of diamonds but was not involved in the new study. “The previous age constraint for Argyle was younger, and it was a lot less clear how to frame the eruption in a broader geological context,” Smith says. He thinks the new study adds exciting evidence that these “eruptions are related to bigger processes that affect whole continents rather than being isolated, random burps of magma.”
Olierook thinks similar events may have occurred at other continental boundaries around the world. Most diamond-bearing deposits are found in the middle of continental plates where rock is exposed. This makes Argyle an outlier. When the mine was first discovered, most geologists thought that searching for diamonds along continental plate boundaries which are often uplifted by ancient mountain belts and buried beneath soil and sand was futile.
Though gem mining in these regions remains difficult, Olierook believes there are plenty of diamonds to be found in the rough. “I think all of them will host some sort of coloured diamonds,” he says. “They may all be brown, but with a little bit of luck, there could be a few pinks in there.”
Rio Tinto has unveiled the latest heirloom piece of Argyle Pink Diamonds jewellery, featuring one of the last diamonds to be mined from the iconic Argyle mine in the East Kimberley, Western Australia.
Mining ended at Argyle in November 2020, after 37 years of uninterrupted production, during which the mine became the source of about 90% of the world’s prized rose-to-magenta hued stones. The mine produced more than 865 million carats of rough diamonds.
Designed by Western Australian jeweller Solid Gold Diamonds, the Argyle Rose features a total of 3.25 carats of rare Argyle pink and blue diamonds encrusted in a rose motif, surrounded by white diamonds and hand-set in platinum and 18 karat gold.
The heart of this piece is an extremely rare 1.36 carat, Fancy Deep Pink radiant cut diamond. It is just one of twelve radiant cut diamonds over one carat with a colour grading, 1P, from the last 30 years of production from Argyle.
The surrounding petaled design of pink and blue Argyle Diamonds totals 1.89 carats, together with 2.80 carats of white diamonds. The Argyle Rose is for sale at Solid Gold Diamonds in Perth for A$2 million.
“I am delighted to launch the Argyle Rose. Encapsulating a rich history and an extraordinary provenance, it is both a contemporary treasure and an heirloom for tomorrow,” Sinead Kaufman, Chief Executive of Rio Tinto Minerals said in a statement.
“These rare and precious diamonds are one and a half billion years old, from one of the most beautiful places on earth, and the world is simply not producing them anymore.”
A pair of pear-shaped fancy pink pendant diamond earrings, weighing 11.17 carats and 10.85 carats, are to be sold at Sotheby’s Hong Kong.
The estimate is $5.48m to $7.01m. Both diamonds are GIA-certified as Fancy Pink, Natural Color, VVS1 Clarity.
The pink diamonds are set in platinum and yellow gold suspended from a pear, marquise-shaped and brilliant-cut diamond surmount weighing a total of approximately 6.5-7.5cts, mostly F-H color, average VS-SI clarity.
The lead tomorrow’s Magnificent Jewels I. The sale also includes a Harry Winston diamond fringe necklace with nine pear-shaped diamonds weighing 14.93 to 2.04 carats (estimate $4.46m to $6.37m) and a 5.49-carat fancy intense blue diamond ring (estimate $4.84m to $6.37m).
The new Tiffany Collection comprises 35 gems, including an unusual red stone, from the Argyle Diamond Mine in Australia.
About a year ago, a representative of the Argyle Diamond Mine — a site in Western Australia that was the pre-eminent source of pink diamonds until it closed in 2020 — approached Tiffany & Company’s chief gemologist with an unusual offer: the chance to purchase a collection of diamonds that were among the last stones taken from the mine.
The decision, Tiffany executives said, didn’t require much consideration.
“We had to do it,” Anthony Ledru, the brand’s president and chief executive, said in his bright office in New York’s Flatiron district. “It’s perfect with what we stand for.”
The purchase, which was finalized several months ago, involved 35 diamonds of various shades: pink, almost purple and even one red gem, an especially unusual color for a diamond. The gems, which had already been cut in various styles, “checked off all of those boxes: rarity, scarcity and beauty,” said Victoria Reynolds, Tiffany’s chief gemologist.
But the stones are small, ranging from 0.35 carats to 1.52 carats, considerably more petite than the statement-size gemstones frequently used in engagement rings and solitaire necklaces.
“These are small, there’s no doubt,” Ms. Reynolds said, “but for connoisseurs, collectors who understand how rare these are, it’s incredibly appealing.”
How much did the jeweler pay for what it now calls the Tiffany Collection? Mr. Ledru wouldn’t disclose the sum, but said it was “probably not enough compared to what it’s going to become in the next five, 10 years.” (He did note that it was Tiffany’s largest single purchase of 2022.)
Exactly how the diamonds will be used in jewelry hasn’t been decided, although Mr. Ledru said it was likely that they all would be used in one-of-a-kind designs. In the meantime, the diamonds are being shown to select clients in New York City and, next month, in Doha, the capital of Qatar.
The eventual prices are sure to be high. “You pay a premium for anything that says ‘Argyle pink diamond,’” said Renée Newman, an independent gemologist and author based in Los Angeles.
