A stunner in every way, the gem meets the criterion for a near-perfect stone. The sophistication of the stone is reserved for the finest diamonds, evocative of important stones found in the fabled mines of India's Golcondo region and several other mines in Brazil and South Africa.

The gem has perfect symmetry with a cut so precise it can stand totally balanced on its pointed end or cutlet. In addition, the diamond has no traces of colorant nitrogen, the feature that gives the stone such transparency and sparkle. Only 2% of all diamonds need this chemical. "The old-world charm of this beautiful gem, along with a softness to its cut and its superb brilliance, ranks it among some of the most wonderful diamonds to have appeared for sale at Christie's, such as the historical Polar Star, to [which] it bears a striking resemblance," said Rahul Kadakia, head of Jewelry Americas at Christie's.

The Polar Star diamond is one of the famous diamonds in the world, having been owned by Russian royalty until its sale to the House of Cartier in the 1920s, and later on selling at Christie's Geneva in 1980 for $5.1 million, a huge sum at the time.