The Polar Star diamond is a 41 carat cushion cut diamond, from the famous Golconda region in India. It was named after Polaris, the Northern Star.
It has an eight pointed star arrangement on its lower pavilion, from which it derives its name. The symmetry of the cut is so precise that it can be balanced on its culet, which would probably make it the most perfectly cut historic diamond in the world.
First owned by Joseph Bonaparte (eldest brother of Napoleon) in 1806, it was sold some time in the 1820s to the Youssoupov family, one of the richest families in Russia. It passed by descent to Prince Felix Youssoupov, who brokered it to Cartier in 1924. It was bought by Sir Henry Deterding, a Dutch industrialist, who gave it to his wife, Lynda. She died in 1979. In 1980 it was sold for 4.6 million dollars, at that time a record price for a diamond.
It was bought by a Sri Lankan diamond merchant, and has not been seen since.
A 2006 painting of the Polar Star by Damien Hirst sold in 2011 at Christie’s New York for 362,500 dollars.
The Gubelin gem laboratory in Geneva has a detailled report on the stone. It weighs 41.28 carats, and has a slightly flat crown and a large table. The girdle of the diamond is slightly abraded, but that could be easily repaired with little weight loss. It is E colour, with a trace of pink, and has blue flourescence. This combination of high colour and flourescence is not uncommon in Golconda diamonds. It is a type IIa diamond, a very rare classification. (see HERE for more about diamond types). For scale, here is a life sized model alongside a two euro coin.