The Koh-i-Noor: The Full Story of the World's Most Contested Diamond

The Koh-i-Noor — Persian for "Mountain of Light" — is a 105.6-carat oval brilliant diamond that sits today in the Tower of London, set in the crown made for the Queen Mother in 1937. It came to Britain in 1849, when the ten-year-old Maharaja Duleep Singh signed a treaty surrendering it to Queen Victoria after the Second Anglo-Sikh War. Four nations — India, Pakistan, Iran and Afghanistan — have since asked for it back, which is why this single stone is often called the most contested diamond on Earth. We told its story briefly in our tour of the most famous diamonds in history; this is the long version, told properly.

The Koh-i-Noor at a glance

Out of the river gravels of Golconda

Nobody knows when the Koh-i-Noor was found, or by whom. What we can say with confidence is where: the diamond fields of the Golconda region in southern India, where for centuries workers sifted river gravels by hand. Until deposits were found in Brazil in the eighteenth century, this was essentially the only place on Earth producing diamonds — the source of nearly every legendary stone of the age. (If you're curious how such stones form at all, our diamond guide covers the science.)

The early paper trail is genuinely murky. Romantics have linked the Koh-i-Noor to gems mentioned in Sanskrit epics, and some historians once identified it with a great diamond described in the memoirs of Babur, the first Mughal emperor. Modern scholars are far more cautious: several enormous Golconda diamonds circulated through Indian courts, and the records rarely make clear which was which. The first descriptions that can be tied to the Koh-i-Noor with reasonable confidence come only from the 1740s. Everything before that is educated guesswork — worth telling, but worth labelling honestly.

The Peacock Throne and the sack of Delhi

By the seventeenth century the diamond had, by most accounts, entered the treasury of the Mughal emperors — then perhaps the richest rulers in the world. Shah Jahan, the emperor who built the Taj Mahal, commissioned the Peacock Throne: a jewel-encrusted golden platform that took years to complete and, by some accounts, cost around twice as much as the Taj itself. Tradition holds that the Koh-i-Noor was among its stones, possibly set in the head of one of the throne's peacocks — though, as with so much of this story, the sources don't fully agree.

The turning point came in 1739. Nader Shah, the brilliant and ruthless ruler of Persia, invaded a weakened Mughal empire, defeated its army and occupied Delhi. What followed was one of the most devastating sackings in the city's history, and Nader Shah rode home with a caravan of plunder that included the Peacock Throne and the great diamond. A much-loved tale says that on first seeing the stone he cried out "Koh-i-Noor!" — Mountain of Light — giving the diamond its name on the spot. It's a wonderful story, and it may even be true, but it is best treated as legend: the earliest tellings appear well after the event. What is certain is that from 1739 onward, the diamond carried its Persian name.

Kabul, Lahore and the Lion of the Punjab

Nader Shah did not enjoy his prize for long. He was assassinated in 1747, and in the chaos that followed, the diamond passed to Ahmad Shah Durrani, one of his commanders, who went on to found the Afghan empire. For some seventy years the Koh-i-Noor stayed with the Durrani dynasty as Afghanistan's rulers rose, fell and blinded one another in succession struggles.

By 1813 the deposed Afghan king Shah Shuja was living in Lahore as the uneasy guest of Maharaja Ranjit Singh, founder of the Sikh Empire and remembered as the Lion of the Punjab. Ranjit Singh wanted the diamond, and after prolonged pressure — accounts range from hard bargaining to something closer to coercion — Shah Shuja handed it over. The Maharaja wore it not in a crown but strapped to his arm in an armlet, displayed at festivals and durbars as the visible proof of Sikh power.

A ten-year-old's signature

Ranjit Singh died in 1839, and his empire unravelled with brutal speed — a decade of court intrigue and assassination that left his young son Duleep Singh on the throne as a child. Two Anglo-Sikh Wars followed, and in 1849 the British East India Company annexed the Punjab. The Treaty of Lahore that sealed the annexation contained a clause written specifically for one object: the gem called the Koh-i-Noor was to be surrendered by the Maharaja of Lahore to the Queen of England. Duleep Singh, the Maharaja in question, was ten years old. He signed. Whatever one's view of the legal formalities, it is hard to describe a treaty imposed on a child by the army occupying his capital as a freely given gift — and that fact sits at the heart of every argument about the diamond to this day.

The stone's voyage to Britain in 1850 aboard HMS Medea has passed into lore: by various accounts the ship endured a cholera outbreak and a ferocious storm on the way, with the diamond locked in a small safe. It reached England in the summer of 1850 and was presented to Queen Victoria.

The Great Exhibition flop — and the 1852 recut

In 1851 the Koh-i-Noor went on public display at the Great Exhibition in London, and the public queued in their thousands to see it. They came away underwhelmed. The stone still carried its old Mughal-style cut, made to preserve weight rather than to catch light, and in its gloomy display case it simply refused to sparkle. The organisers reportedly tried gas lamps and mirrors; nothing worked.

Prince Albert, stung by the disappointment, drove the decision to recut it. In 1852 the work was carried out in London under the royal jewellers Garrard, using a specialist cutter brought over from the famous Coster workshop in Amsterdam, with the elderly Duke of Wellington making the ceremonial first cut. Weeks of grinding later, the diamond had become a shallow oval brilliant — far livelier, but reduced from roughly 186 carats to 105.6, a loss of over 40 per cent that Albert is said to have privately regretted. It remains one of history's great cautionary tales about cutting: brilliance always comes at a price in weight.

The curse, the queens and an empty crown

Then there is the famous tradition — often quoted, of uncertain age — that the Koh-i-Noor brings misfortune to any man who wears it, and that only God or a woman may wear it safely. Given the fates of many of its male owners, from Nader Shah to Shah Shuja to Duleep Singh, you can see why the tale took hold. We'd file it firmly under legend, but it is a legend the British royal family has, in practice, respected: since Victoria, the diamond has been worn or set only in the crowns of queens. It was mounted in the coronation crowns of Queen Alexandra in 1902 and Queen Mary in 1911, and finally in the platinum crown made for Queen Elizabeth, the Queen Mother, in 1937 — the crown in which it still sits at the Tower of London.

In 2023 that quiet tradition met modern politics. For the coronation of King Charles III, Queen Camilla chose to reuse Queen Mary's crown, reset with diamonds cut from the Cullinan — and conspicuously without the Koh-i-Noor. Buckingham Palace framed the reuse of an existing crown as a matter of sustainability and efficiency; it said nothing about the absent diamond, and the omission was widely read as a way of keeping the world's most contested stone out of the ceremony.

Four nations, one diamond

India has requested the diamond's return on several occasions since independence, pointing to its Indian origin and the circumstances of the 1849 surrender. Pakistan notes that Lahore, where the stone was surrendered, lies within its borders. Afghanistan cites the seventy years the diamond spent with the Durrani dynasty, and voices in Iran point to Nader Shah and the Persian name the stone still carries. Britain's position has been consistent: the Koh-i-Noor was transferred legally under the Treaty of Lahore, and successive governments have declined to reopen the question. Each claim is sincere, each rests on a real chapter of the diamond's history, and they cannot all be satisfied — which is precisely why the Koh-i-Noor has become a symbol of the wider debate about empire and restitution. We won't pretend to adjudicate; the honest summary is that the stone's history is so tangled that even its rightful home is a matter of perspective.

At Signora, we spend our days with diamonds whose stories are refreshingly simple: grown in modern facilities, cut for light rather than legend, and owned — happily and unambiguously — by the person wearing them. If the Koh-i-Noor's tale has left you curious about how lab-grown and natural diamonds compare, or you'd like to begin a far less contested story of your own with one of our made-to-order engagement rings, we're always glad to talk it through.