The 64 diamond collection, including three fancy red diamonds and weighing 56.28 carats in total, make up the 2019 Argyle Pink Diamonds Tender.

Rio Tinto Copper & Diamonds vice president of sales and marketing Mr Alan Chirgwin said he was delighted to be in New York, the epicentre of the fancy coloured diamond industry.

"It is 40 years since the discovery of Rio Tinto's Argyle mine and it remains the first and only ongoing source of rare pink diamonds in the world, in history," he said.

"With the lifecycle of this extraordinary mine approaching its end, we have seen and continue to see, an unstoppable demand and strong value appreciation for these truly limited edition diamonds."

Rio Tinto is also showcasing in New York its Argyle Pink Everlastings collection, an offering that has been curated to showcase the full colour palette of Argyle pink diamonds weighing 0.14 carats and below.

The collection will be tendered alongside the 2019 Argyle Pink Diamonds Tender with bids closing on October 9.

In conjunction with the tender, Rio has unveiled ‘Argyle Dreaming', a one-off necklace and ring worth US$1.1 million.

The pieces were created by famed international designer, master craftsman and jeweller John Calleija.

Comprising 673 pink, white, yellow, blue and champagne Argyle diamonds and 237 grams of Rio Tinto's Kennecott gold, Argyle Dreaming took over 800 hours to create.

The Argyle Dreaming necklace and ring will be showcased in New York and London before returning to Calleija's stores in Australia.

The Argyle diamond mine, in Western Australia's Kimberley region, is the world's largest producer of coloured diamonds. The mine is set to close next year due to depletion.