Oprah Winfrey, queen of television, champion of the downtrodden, benefactor extraordinaire, and confidante of the rich and famous, can now add another title to her collection – Queen of Diamonds.

During Oprah’s recent Australian tour, each member of her 6,000-strong Sydney audience was gifted something uniquely Australian yet universally coveted - a white gold necklace featuring Rio Tinto Ltd's famous Argyle diamonds

The one-off necklace, shaped in an 'O' in 'Australian colors' features seven diamonds including a rare pink Argyle diamond mined from Rio Tinto’s operations in Western Australia's Kimberley region.

The Argyle diamond mine is the world's largest source of colored diamonds, including whites, champagnes, cognacs, blues, greens and the rarest of all, pink diamonds.

More than 90 per cent of the world's pink diamonds come from Argyle.