This beautiful blue diamond reportedly is nearly flawless.

The 5.16 carat, pear-shaped internally flawless Fancy Vivid Blue gem is the first diamond of its kind to appear at an auction from the collection that De Beers, the world’s largest diamond producer, presented in 2000 to celebrate the Millennium. It is being put up for sale by a private collector and is the star lot at Sotheby’s Hong Kong jewels and jadeite 2010 spring sale on April 7 and bidding is expected to reach the £3.8 million ($5.8 million) estimate price. – From Telegraph