SMI 12: Koh-i-Noor with an amulet.Date: Before 1851Origin: Possibly Kullar Mines, India. The Koh-i-Noor diamond depicted in 1851. During the time of the Sikh Empire of Maharajah Ranjit Singh (1780 – 1839), it was worn around the arm and was considered the most expensive diamond in the world. Composed of