The auction house Sotheby's has had a good week. Not only was it was lucky enough to set a record price for auctioning the work of American artist Andy Warhol, but also in selling the most expensive diamond in the world. 

The huge amount paid for the 'Pink Star', was actually spent in Geneva – the lot was bought for 68 million Swiss francs (74.1 million dollars).

According to the head of the European and Middle East Branch of Sotheby's International Jewellery, David Bennett, the stone is "the biggest and the most flawless of all pink diamonds known to date." The treasured oval-cut gem weighs 59.6 carats.