When it comes to a solid investment, few options can match the performance of Argyle pink diamonds. Over the past two decades, the value of these rare stones has soared by 500%, far outpacing the returns of major equity markets. And their worth has only increased with time: earlier this month, the Argyle Diamond Mine in Western Australia, which supplied 90% of the world’s pink diamonds, officially closed.

Pink diamonds are highly sought after not only for their stunning beauty but also for their extreme rarity. While the exact cause of their unique pink hue remains a mystery, it’s believed to be the result of a twist in the stone’s atomic lattice during its formation over a billion years ago. Regardless of the scientific explanation, the result is a stunning gem that ranges in color from soft pink to deep, saturated pink and violet, sparkling with the brilliance that only a diamond can provide.

The Value of Rarity and Elegance

In November 2020, Sotheby’s set a new record when it sold a 14.83-carat vivid purple-pink diamond in Geneva for an astonishing $26.6 million. As the largest diamond of its kind ever to be auctioned, this sale marked a rare moment in the world of luxury that may not be repeated for quite some time.

“Pink diamonds have captivated collectors for centuries, more than perhaps any other colored diamond,” says Gary Schuler, Worldwide Chairman of Sotheby’s Jewelry Division. He notes that pink diamonds account for five of the ten most valuable diamonds ever sold at auction.

“These extraordinary sales, all achieved in the last decade, reflect the growing recognition of how scarce these natural wonders are,” Schuler continues. “As the supply of these stunning stones continues to shrink, their value is likely to rise even further.”

The closure of the Argyle mine, Schuler notes, will inevitably impact the delicate balance of supply and demand for colored diamonds, and, in turn, affect their market value.

Before the mine’s closure, acquiring Argyle’s precious pink diamonds—particularly those over one carat—was already an extremely rare opportunity. In its 37 years of operation, the Argyle mine produced over 865 million carats of rough diamonds, but only 0.13% of them were pink diamonds of high enough quality to be included in the annual Argyle Pink Diamond Tender. In fact, the number of Argyle pink diamonds larger than half a carat produced in an entire year could easily fit into the palm of your hand.

With so few available, the Argyle mine sold these coveted diamonds (usually around 60 per year) through a tightly controlled process. An exclusive group of around 100 dealers, collectors, and jewelers, all invited by special request, would submit sealed bids for the chance to own these extraordinary gems. This process ensured that only the most qualified buyers had access to these rare treasures.

A Legacy of Rare Beauty

One of the Argyle mine’s most loyal buyers, L.J. West, a prominent New York jeweler, began bidding on the coveted pink diamond tenders in 1990. In the aftermath of the September 11 attacks, when the market was uncertain, the company acquired a rare four-carat vivid pink diamond—the largest ever offered in a tender. “It was a significant moment for us,” recalls Scott West, co-owner of L.J. West. “Since then, prices have soared, and I expect that trend to continue.”

“Argyle pink diamonds are not only breathtaking in beauty, but they also carry a rich history and immense significance,” West adds. “With the closure of the mine, I believe these diamonds will continue to capture the imaginations of collectors for generations to come.”

The Historic Journey of Natural Pink Diamonds

The Argyle mine holds a legendary place in the history of colored diamonds. Before its discovery, colored diamonds were so rare and expensive that they were almost entirely unknown to the public and only traded in the hands of a select few.

However, when the Argyle mine opened, it changed everything. The mine produced an abundance of smaller-sized pink diamonds, making them accessible to a broader range of jewelry designers and increasing their visibility in the luxury market.

The discovery of the pink diamond mine by Rio Tinto is nothing short of remarkable. “Fifty years ago, few would have believed that diamonds could be found in Australia,” says Robyn Ellison, Communications Manager at Rio Tinto Diamonds.

While diamonds were first discovered in Australia during the 1850s, it wasn’t until more than a century later that the search resumed. In the early 1970s, geologists began exploring a remote region of Western Australia roughly the size of Texas. After seven years of frustrating exploration, they stumbled upon four small diamonds in a dry creek bed, which ultimately led them to the discovery of the Argyle mine in 1979.

Building the infrastructure for the mine and developing the necessary technology to make it operational was no small feat. Alluvial mining began in 1983, followed by open-pit mining two years later. By 2013, Argyle had fully transitioned to an underground operation. The final load of rough stones left the mine on November 3 of this year, marking the end of an era.

What’s Next for the Highly Sought-After Natural Pink Diamonds?

Those fortunate enough to be invited to the penultimate Argyle Pink Diamond Tender in December 2020 were given a rare opportunity to acquire diamonds directly from the mine, likely at record-breaking prices. The collection featured an impressive range of colors from pink, violet, blue, purple-pink, to red, with 62 polished pink diamonds up for grabs.

Among them, 21 were over one carat, and three exceeded two carats. Additionally, there were 12 curated sets of miniature Argyles. Notably, two standout stones from this collection were the Argyle Eternity, a 2.24-carat fancy vivid purplish-pink round diamond, and the Argyle Ethereal, a 2.45-carat fancy intense purple-pink square radiant cut.

In 2021, the final Argyle Pink Diamonds Tender featured the best pinks from the 2020 production, marking the end of an era for the mine. While the mine may now be depleted, Argyle pink diamonds will continue to be a prized collectible for generations, much like the Golconda mine’s legacy, which is still remembered as the source of the world’s finest colorless diamonds, even long after it closed.