The Monk Diamond is famous for its distinctive green color.
A Russian nobleman bought the diamond for his wife in 1889, but it was stolen during the Russian Revolution. For the next 30 years, the Monk Diamond's whereabouts were unknown.
In 1947 it was discovered during a police raid on a gang of petty criminals in Moscow.
It was returned to the nobleman's family. The nobleman's son decided the Monk Diamond was unlucky and sold it to the House of Volkov, Moscow oldest jewellery house.
The House of Volkov paid and undisclosed sum for the jewel, but it was rumoured to be the most expensive diamond sale ever.