Diamond jeweller Rohan Milne built a career working with rare gems. Then came a mysterious offer

When Perth jeweller Rohan Milne received an email offering to sell him stolen diamonds, he did not hit the delete button.

Instead, it piqued his interest. 

The splashy diamond brochure didn't come from a nefarious source.

It was from one of the world's biggest diamond miners – Rio Tinto.

The blurb was marketing gold.

"From out of the vault comes a collection of precious diamonds," the Argyle brochure read.

"These diamonds hold the secrets of a colourful chapter in Argyle's history and bring to light a riveting account of temptation and desire."

The diamonds were put out to tender by Rio Tinto when it was clearing out its vaults during the recent closure of its Argyle diamond mine in Western Australia's Kimberley region.

The mysterious diamonds were some of the gems recovered by police from a diamond heist that happened at the mine in the late 1980s and 90s.

The package of 20 diamonds also came with a great name: The Argyle Intrigue.

Even for a diamond atelier, it is not every day Rohan Milne receives an email like this one.

Based in Perth, Rohan was part of an elite group of jewellers throughout the world that had the exclusive rights to bid for the most outstanding pink diamonds that were mined from Argyle.

"That network received an email from Argyle stating that due to the process of closing down the mine … they had found the parcel of diamonds," Rohan says.

Argyle mined its last diamonds in November 2020, putting an end to the world's steady supply of vivid pink sparklers.

With no more pink diamonds in the pipeline, the price of Argyle pinks has soared.

New generation of diamantaire

The world's love of diamonds is steeped in history with trading of stones in India dating as far back as the fourth century BC.

Diamond trading houses are largely family businesses handed down from generation to generation with many of the world's diamantaires based in the big centres of Antwerp, Geneva, New York and Hong Kong.

Rohan is the first to admit a diamantaire is not a usual career path for a boy from Perth.

"The guidance officer at school actually had said to me, 'Look, there are no jobs for jewellers,'" he says.

"'You have to be involved in a family,' [Rohan was told], 'generally they take on their extended family because of the nature of what you're dealing with.'"

Undeterred, Rohan did his jewellery apprenticeship and after graduating, set off around the world.

After a few years of designing jewellery in New York, he traded in the streets of the Big Apple for the cobblestones of Rome.

There he landed a job making jewellery for the Pope, the head of the Catholic Church, Vatican City and the Holy See.

"There are all those stories of back in the day, you know, thousands of years ago within the Holy See and the different orders, and the wars that transpired back then," he says.

"But those orders still exist within the Holy See.

"They all have different ranks, and they all wear different colours, or different pins, to denote their ranking within the orders."

Under the guidance of a maestro, Rohan made decorazione: ceremonial jewellery that the Pope would bestow to his cardinals.

"The company that I was working for, they'd been doing it for centuries," he says.

"And the maestro, he was in his mid-70s at the time, but he was still doing everything by hand.

"He still hand made the coin stamps for the old royal family … there is no longer a royal family of Italy, but some of those old royal families of Italy.

"It was about doing things right."

Rohan says the experience was so surreal there were times he had to pinch himself.

"There was moments where, you know, we had cardinals and the street would get blocked off with the Swiss Guard in civilian clothes," he says.

"A cardinal would come in.

"I was in my mid to late 20s and there'd be a cardinal sitting 2 metres away from me.

Cufflinks crafted by Rohan were given as a gift to Pope John Paul II.

Eventually, Rohan and his wife Toni returned to Perth to set up a jewellery business.

It is one of 35 ateliers in the world that will continue to sell Argyle pink diamonds.

"We were the youngest by probably a generation to be given the opportunity," he says.

A Rio Tinto spokesperson says the miner will work with Argyle pink select ateliers like Rohan's to market the last of the pink diamonds it stockpiled.

"Even though the mine has closed," Rohan says, "we still now have a reputation for working with … the rarest gems in the world."

And as for that intriguing email Rohan received from Argyle?

Well, he decided to take a punt and bid for the mysterious diamonds.

Listen to the Expanse: Pink Diamond Heist podcast.