The Koh-i-Noor, Persian for Mountain of Light, is one of the most historically documented diamonds in the world. It is presently set in the front of the Crown of Queen Elizabeth the Queen Mother, on display at the Tower of London with the rest of the British Crown Jewels. In its current cushion-cut form the stone weighs 105.602 carats, having been recut from a larger Mughal-cut original of approximately 186 carats in 1852 under the direction of Prince Albert.

Origin

The Koh-i-Noor is generally accepted to have originated from the Kollur Mine in the Golconda region of southern India, the alluvial diamond field that produced most of the great historical Indian diamonds before the discovery of the African deposits in the 1860s. Documentary evidence places the stone in the possession of the Kakatiya dynasty of southern India in the early fourteenth century, from which it passed through the Khilji and Tughluq dynasties of Delhi, and subsequently into the treasury of the Mughal emperors after Babur's conquest of northern India in 1526. The stone is mentioned by name in Babur's memoirs, the Baburnama, although the identification with the modern Koh-i-Noor depends on a chain of inference that has been disputed in the academic literature.

From Persia to Britain

After the sack of Delhi by Nadir Shah of Persia in 1739, the stone passed to the Persian treasury, and on Nadir Shah's death in 1747 to his Afghan general Ahmad Shah Durrani, founder of the Durrani Empire. Through several further transfers among Afghan and Sikh rulers it came into the possession of Maharaja Ranjit Singh of the Sikh Empire in 1813. After the British annexation of the Punjab in 1849, the stone was ceded to Queen Victoria under the terms of the Treaty of Lahore, signed by the ten-year-old Maharaja Duleep Singh under controversial circumstances. It was presented to the Queen on 3 July 1850.

Recutting and current form

The Mughal cut of the Koh-i-Noor, a large, somewhat lumpy stone weighing approximately 186 carats, was assessed at the 1851 Great Exhibition and judged disappointingly unbrilliant by Victorian standards. Prince Albert commissioned the firm of Coster of Amsterdam to recut the stone, and in thirty-eight days of work in 1852 the diamond was reduced to its present 105.602-carat cushion-shaped brilliant. The recut substantially improved the optical performance but represented a loss of nearly half the original weight, a decision that has been criticised in subsequent centuries as a destructive intervention.

Setting and ownership disputes

The stone was set in successive royal crowns: first as the centre stone of the brooch worn by Queen Victoria from 1853, then in the crown of Queen Alexandra from 1902, and finally in the front of the Crown of Queen Elizabeth the Queen Mother from 1937, where it remains. The Indian, Pakistani and Afghan governments have at various times made formal claims for the stone's return; the British position, maintained consistently across successive governments, is that the cession under the Treaty of Lahore was lawful and that the stone is the property of the Crown.

Curse and lore

A persistent legend holds that the Koh-i-Noor brings misfortune to male owners. The lore is treated in detail in the related entry on the Koh-i-Noor curse. The stone has, by tradition, been worn only by female members of the British royal family since its acquisition, a custom observed since Victoria's reign.