An extremely rare, flawless blue diamond ring is going on auction today in Hong Kong and is expected to fetch a shimmering $5.8 million. The 5.16-carat gem is one of 12 diamonds originally from the DeBeers Millennium collection, displayed in London to celebrate the new century. The pear-shaped diamond is the first of the collection to be auctioned and is known as "fancy vivid," the highest grade for a color diamond.
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