"It's a 76.02 carat cushion-shaped D-colour diamond (considered to be the most flawless), from the famous Golconda mines in India," Christie's senior international specialist Jean-Marc Lunel told AFP.

The colourless gem, which is about the size of a domino and 1.5 centimetres (more than half an inch) thick, is to be exhibited from October 13th in New York, Hong Kong and Geneva before the auction in Switzerland on November 13th.

Described as the "star lot of the fall jewellery auction season" by Christie's, the diamond has the same provenance as other illustrious jewels including the Koh-i-noor — part of the crown jewels held in the Tower of London — and the Regent, believed by many to be the finest diamond in the French crown jewels and now in the Louvre museum in Paris.

All three jewels come from the now closed Golconda mines, which produced the purest gems, Lunel said.

Next month's auction will be the second time Christie's has sold the Archduke Joseph after it fetched $6.5 million at a Geneva sale in 1993.

The jewel, which belonged to Archduke Joseph of Austria (1872-1962), was put in a vault of the Hungarian General Credit Bank in 1933 by his son, the Archduke Joseph Francis.

The diamond was sold three years later to an anonymous buyer who left it in a safe during World War II, escaping the attention of the Nazis.

It finally resurfaced in 1961 at auction in London and was offered for sale in November 1993 at Christie's Geneva.

Since then the diamond has changed hands privately, but Christie's declined to comment on the identity of the current owner.

The auction house holds eight major jewellery sales a year, including two in Geneva.

"The first half of 2012 saw record sales, thanks mainly to the May auction in Geneva," said Lunel, "when part of the jewellery collection of billionairess Lily Safra was sold for good causes."