How Much Is the Kohinoor Diamond Worth? Why It Has No Price

Nobody knows what the Kohinoor is worth, because it has never been sold and almost certainly never will be. The estimates you'll see, from about $150 million to over $400 million, are guesses stacked on top of each other. What we can say is what it weighs, what comparable diamonds have actually sold for at auction, and why the real value of this stone has very little to do with carats.

The stone

The Kohinoor ("Mountain of Light") is a 105.6-carat oval brilliant-cut diamond. It was recut in 1852 on Prince Albert's orders from its original 186-carat Mughal cut, which was considered dull by Victorian taste, and lost more than 40% of its weight in the process. It's set in the front cross of the crown made for Queen Elizabeth, the Queen Mother, in 1937, and sits in the Tower of London with the rest of the Crown Jewels.

It isn't the biggest diamond in the collection. The Cullinan I in the Sovereign's Sceptre is 530 carats, five times larger. The Kohinoor is famous for its story, not its size.

Why it has no price

A price is what someone paid. The Kohinoor has changed hands many times over the centuries, by conquest, tribute, inheritance and treaty, but never by sale. The last transfer was the Treaty of Lahore in 1849, when the East India Company took it from the ten-year-old Maharaja Duleep Singh after annexing Punjab and presented it to Queen Victoria.

It's held in the Royal Collection in trust for the nation, which means it isn't the monarch's to sell. There is no insurer's figure on record either. So every number you see is an estimate of what a 105-carat historic diamond might bring if the impossible happened and it came to auction.

What comparable diamonds have sold for

Large, famous diamonds do come to auction occasionally, and those sales give a floor:

• The Pink Star, 59.6 carats, sold for $71.2 million in 2017.
• The Oppenheimer Blue, 14.6 carats, $57.5 million in 2016.
• The Wittelsbach-Graff, 31 carats with a royal history, $24.3 million in 2008.
• The Cullinan Dream, 24 carats, $25.4 million in 2016.

On carats alone, a 105-carat colourless diamond of good quality would sit somewhere in the tens of millions. The Kohinoor isn't a top-grade stone by modern standards: its old cut has a flat, wide shape, and it isn't flawless. Judged purely as a diamond, it would be outsold by several stones on that list.

What pushes the estimates into the hundreds of millions is provenance. A diamond that was owned by Mughal emperors, Persian shahs, Afghan rulers, the Sikh Empire and the British monarchy, and that three countries have formally asked for back, would attract the kind of bidding that has nothing to do with the stone's grade. That's where the $150 million to $400 million figures come from, and it's why they're so wide apart: nobody can model what a one-off like that would do in a sale room.

Who claims it

India, Pakistan, Iran and Afghanistan have all claimed the Kohinoor at various points. India's claim is the most active. In 2016 the Indian government told its Supreme Court the diamond had been "gifted" to the British, then backed away from that position after public outcry, and has since said it will keep pursuing its return through diplomacy. Britain's position has been consistent since the 1940s: it stays. The dispute is a large part of why it was left out of Queen Camilla's crown at the 2023 coronation.

What this means for your diamond

Not much, except as a lesson in how value works. A diamond's price has two parts: the stone, which can be graded and compared to recent sales, and the story, which can't. For almost everything you'll ever own, the story adds nothing and the stone is what sells. For a tiny number of objects, the story is the whole price.

If you have a diamond and want to know what it's actually worth, the stone is what matters: carat, colour, clarity, cut and whether it has a certificate from GIA or a comparable lab. Our guide to finding out what an antique is worth covers the method, and for diamond jewellery in particular the honest answer is that resale value runs well below retail, as our page on lab-grown diamond resale value explains. The Valued app will identify a piece from a photo and give you a starting estimate.

Common questions

How much is the Kohinoor worth in dollars?

There's no real figure. Estimates range from about $150 million to over $400 million, but the diamond has never been sold or formally valued. The most expensive diamond ever sold at auction, the Pink Star, fetched $71.2 million.

Is the Kohinoor the most valuable diamond in the world?

Not by weight or grade. The Cullinan I is five times larger, and several modern diamonds are better cut and better quality. Its value is in its history, which is impossible to price.

Why doesn't Britain return the Kohinoor?

Britain's position is that it was legally ceded under the 1849 Treaty of Lahore. India and three other countries dispute that. The diamond is held in trust in the Royal Collection, and successive British governments have refused to return it.

How big is the Kohinoor?

105.6 carats, about 21 grams. It was 186 carats before it was recut in 1852.