It's been worn just three times in 140 years, gracing the necks of two of the most famous women in the world.
Now Tiffany & Co's 128 and a half carat diamond has gone on display in Sydney.
The $40 million gemstone comes with some pretty tight security, as does Kendall Jenner who arrived on an early Qantas flight to the launch of the Tiffany & Co flagship store in Sydney, Nine News reports.
The diamond is on display in the new Australian store, protected by bullet-proof casing.
"The Tiffany diamond is probably the most famous and fancy diamond in the world," says Alessandro Bogliolo, Tiffany & Co CEO who was also present at the launch.
Only three people in the world have been given the honour of wearing the diamond, including Audrey Hepburn and Lady Gaga.
The stone is normally kept at Tiffany & Co's flagship Fifth Avenue store in New York but will remain on display in Sydney for a couple of weeks.