The exciting news is that the Beau Sancy diamond “one of the most important historical diamonds to ever come to auction” will appear in The Magnificent Jewels and Nobel Jewels auction sales due to be held on 14th and 15th May 2012 hosted by Sotheby’s in Geneva.

This was Marie de Medici’s diamond. Marie was from the powerful Florentine family, the daughter of Francesco de Medici, Grand Duke of Tuscany. She wore this diamond at her coronation on 13th May 1610, when she was crowned Queen Consort to Henri IV of France.

Perhaps the diamond did not bring her much luck as her husband was assassinated the day after her coronation?

It is a 34.98ct pear double rose cut diamond. It has an estimate of between £1.2 million and £2.5 million.

The diamond remained in the royal families of France, England and Prussia. This auction will see over 700 pieces of fine jewellery go on sale including many important historical and royal precious jewels however this diamond is the star lot.