The gem was found at Rio Tinto's Argyle mine Canberra - Arabstoday Pink diamonds are one of the most valuable jewels in the world - and now Rio Tinto miners in Australia have unearthed the biggest ever found in the country. The company's Argyle mine, situated in the Kimberly region, produces a staggering 90 per cent of the world’s pink diamonds and is describing this example as ‘unprecedented’. It has named the 12.76-carat jewel the Argyle Pink Jubilee and the bookies believe it may fetch between £20 and £25million at auction. A diamond of this calibre is unprecedented - it has taken 26 years of Argyle production to unearth this stone, and we may never see one like this again,’ said Argyle Pink Diamonds Manager Josephine Johnson in a statement. Pink diamonds were celebrated in the Pink Panther series of movies. The title refers to a jewel in which the shape of a panther can be seen in it when it’s held up to the light in a certain way. This real life version will be kept safe and secure from cat burglars while it is cut and polished before being sold during Rio Tinto’s annual Argyle Pink Diamonds Tender later this year. How much if fetches depends on how much is hewn off it during the polishing process. Sotheby's Asia department head of jewellery, Chin Yeow Quek, told CNN: ‘It is hard to judge a stone in the rough. It really depends on how large the rock will be polished downed to. It also depends on the [intensity of] colour and clarity.’ He explained that some diamonds lose around 50 per cent of their size during the polishing process. Alex Donohue of Ladbrokes, meanwhile, said: ‘It's odds-on whoever stumps up for the mega-rock will be worth a few quid.’ The record for the most money ever spent on a jewel stands at £29million, paid for a rare pink diamond in 2010. It weighed 24.78 carats and was bought by the British billionaire jeweller Laurence Graff, 72. Dubbed 'The King of Bling' - Mr Graff said that he had bought the gem for himself and immediately named it 'The Graff Pink'. He paid nearly double the previous record which was for the 17th century stone the 'Wittelsbach' blue diamond two years ago. Mr Graff was the buyer on that occasion, too. 'It is the most fabulous diamond I've seen in the history of my career and I'm delighted to have bought it,' said Graff, who left school at 14 to work in London's East End and now resides in the Swiss resort of Gstaad.