In a Paris exhibition, Swiss jewellery maker de Grisogono unveils an 813-carat unpolished diamond bought for $68 million (around 60 million euros), the world’s most expensive rough when it was purchased.<br /><br /> Canadian miner Lucara Diamond sold the stone after unearthing it in Botswana last year.<br /><br /> It has been named ‘Constellation.’<br />No Comment | euronews: watch the international news without commentary | http://www.euronews.com/nocomment/
