The diamond, a cushion-cut fancy intense VS1 gem, is graded 6P, indicating a hue intensity of 6/10 with pink as the dominant colour.

This extraordinary stone is the centrepiece of a 416-lot online auction that concludes on August 11. The auction features a collection of items from the late Graham Jackson, the former owner of Loloma Jewellers in Townsville, Australia, who passed away at 92 in May.

The Argyle Pink diamond was originally sold at the 2021 Argyle Pink Tender, marking Rio Tinto's final collection from the mine before it ceased operations in November 2020. Over its 37-year history, the Argyle mine was renowned for producing 90% of the world's pink diamonds.

Sydney-based First State Auctions is handling the sale, with the diamond expected to fetch between AUD$700,000 and AUD$800,000 (US$455,000 to US$520,000).

This auction follows a significant purchase by Tiffany & Co. in January, when the luxury jeweller acquired a parcel of 35 Argyle pink diamonds, ranging from 0.35 to 1.52 carats, for its select clientele.