The World’s Most Valuable Diamonds

Diamonds are odd things when you really look at them. They begin as carbon and, after an unimaginably long time under heat and pressure deep in the Earth, they turn into stones people queue to see. What makes one diamond expensive is rarely just size. Colour can change everything. Clarity can push a stone into another league. Provenance can turn a gem into a piece of history.

10 of the Most Expensive Diamonds Ever Found

This list is designed for readers searching for the most expensive diamond, the most costly diamond in the world, or the most valuable diamond in the world, but it also helps you understand why these stones reach such eye watering numbers. Some are the biggest diamonds ever found in their category. Some are famous because they shaped history. Others are modern record breakers with confirmed auction totals.

Some diamonds sit in crown collections or museums, so their values are best understood as estimates, not because they are unclear, but because they are not realistically for sale. Others have confirmed prices because they were sold at public auction. That means the highest price diamond on the list might be different depending on whether you are judging by confirmed auction results or by historic stones that are effectively beyond the market.

1.Koh i Noor, priceless

The most valuable diamond in the world. The Koh i Noor, often translated as Mountain of Light, is widely described as the most valuable diamond in the world, and also the most expensive diamond in the world, mainly because it is effectively beyond the market. It is not traded in the normal sense, so there is no genuine sale price to quote. That is why it is regularly called the costliest diamond in the world, but the honest label is priceless.

Its current weight is about 105.6 carats after multiple re-cuttings over time. The early record is debated and incomplete, but today it forms part of the British Crown Jewels and is set in the Crown of Queen Elizabeth The Queen Mother. Because it is unsaleable, any values attached to it are estimates only. You will see big figures mentioned in different sources, but priceless is the most accurate description. 

If you are looking for the most costly diamond in the world in a strict market sense, it becomes more complicated. But if you mean the diamond that sits at the peak of history, symbolism, and cultural importance, the Koh i Noor remains the name people return to.

2. The Cullinan Diamond, about $400 million

Largest diamond in the world, biggest diamond ever found in gem quality rough form. In 1905, South Africa produced the Cullinan, a 3,106 carat rough diamond that remains the biggest diamond ever found in terms of gem quality rough. For many people, it is the simplest answer to the phrase largest diamond in the world, because nothing else matches the scale of its discovery. Even uncut, it changed the boundaries of what people believed nature could produce.

The Cullinan was cut into 105 separate stones. The combined value is often cited at around $400 million, but that number is an estimate because the set is not traded as a single asset. Still, in everyday conversation, this is regularly referred to as a world costly diamond, because the story, the size, and the royal setting make it feel untouchable.

Two stones carry most of the fame. Cullinan I, the Great Star of Africa, is mounted in the Sovereign’s Sceptre with Cross. Cullinan II is set in the Imperial State Crown. Several other Cullinan stones appear in royal jewellery, which keeps the story alive. If you are searching for the most costly diamond or the largest diamond in the world, the Cullinan is the one that dominates the conversation.

3. The Hope Diamond, about $250 to $350 million

Most expensive diamond with a museum legacy. The Hope Diamond is known for its deep blue colour and the folklore that clings to it. It is linked historically to the Golconda region and entered European history via French merchant traveller Jean Baptiste Tavernier before becoming part of the French crown collection. It is one of those stones that proves value is not only about carats, it is about story.

After being stolen during the French Revolution, it resurfaced in London and passed through multiple owners. In 1958 it was donated to the Smithsonian Institution, where it remains on public display. Its value is usually quoted as an estimate in the $250 million to $350 million range, driven by rarity, provenance, and cultural fame rather than a modern sale.

It is sometimes described as the most costly diamond in the world within its category because it combines visibility, mythology, and colour in a way very few stones ever do. If you are searching for the costliest diamond in the world and you care about public fame, the Hope Diamond is always high on the list.

4. De Beers Centenary, $100 million plus

One of the most flawless and costly diamonds ever cut. Discovered in 1986 at South Africa’s Premier Mine, the De Beers Centenary began as a 599 carat rough and was later cut into a 273.85 carat heart shaped diamond with 247 facets. This is the kind of stone collectors talk about in terms of perfection rather than drama, because it is built around exceptional quality.

It is graded D colour and flawless in clarity, a combination that is exceptionally rare at this size. It was widely reported as being insured for $100 million in the early 1990s. The current owner and location have not been publicly confirmed, which is why its value is typically expressed as $100 million plus. It is a strong contender whenever people discuss the most costly diamond, because flawlessness at this scale is simply not common.

5.The Pink Star Diamond, about $71.2 million

Highest price diamond sale for a vivid pink, with a confirmed auction result. The Pink Star is the world’s largest internally flawless Fancy Vivid Pink diamond and one of the most important coloured diamonds ever offered at auction. Mined in 1999, it was cut from a 132.5 carat rough into a 59.60 carat oval diamond.

In April 2017 it sold at auction in Hong Kong for about $71.2 million. You may see small variations in the reported figure due to exchange rate reporting and rounding. After the sale it was renamed the CTF Pink Star after its buyer. For many readers, this is the cleanest example of a highest price diamond because the auction result is confirmed, public, and easy to compare.

6. The Regent Diamond, $60 million plus

A historic contender for the costliest diamond in the world conversation. The Regent Diamond weighs 140.64 carats and is one of Europe’s best known historic diamonds. It was found in India and later purchased in the early 1700s by Thomas Pitt, the governor of Madras, before being sold to the French regent Philippe II, Duke of Orléans, which gave it its name. 

It became part of French royal regalia, survived the Revolution, and today is held in the Louvre Museum. Values quoted for the Regent are estimates, often cited as $60 million plus, reflecting history and quality rather than a recent sale. It is not always the first name people mention, but it is absolutely one of the most valuable diamonds in the world when you look at European royal heritage.

7. Williamson Pink Star, $57.7 million

A most rare diamond example in modern auction history. Fancy Vivid Pink diamonds above 10 carats are genuinely scarce. The Williamson Pink Star is an 11.15 carat Fancy Vivid Pink diamond with internally flawless clarity, cut from a larger rough by specialist cutters.

In October 2022 it sold at auction in Hong Kong for $57.7 million, setting an extraordinary price per carat for a diamond at the time. Part of the appeal is the colour intensity, but the clarity and size are what make it truly uncommon. If you are searching for a most rare diamond, this is one of the best recent examples where rarity directly becomes a world costly diamond headline.

8. The Oppenheimer Blue Diamond, $57.5 million

A modern benchmark for highest price diamond results. The Oppenheimer Blue is a 14.62 carat Fancy Vivid Blue diamond with VVS1 clarity. It sold at auction in Geneva in 2016 for $57.5 million, setting a record for a blue diamond at the time.

Large vivid blues appear at auction only occasionally, and this one arrived with the right combination of size, saturation, and grading, which is why it remains a modern reference point. If your search includes most costly diamond, highest price diamond, or most expensive diamond, the Oppenheimer Blue is one of the cleanest examples with a confirmed public sale figure.

9. De Beers Blue, $57.5 million

The largest vivid blue diamond offered at auction at the time. The De Beers Blue sold at auction in Hong Kong in April 2022 for $57.5 million. It is a 15.10 carat step cut Fancy Vivid Blue diamond and, at the time of sale, it was presented as the largest Fancy Vivid Blue diamond ever offered at auction.

Its importance is not just the price, but the scarcity. Stones in this category rarely reach the open market at all. If you are researching the most expensive diamond and focusing on vivid blues, this is one of the most important entries on any top ten list.

10.The Graff Lesedi La Rona, $53 million plus

From one of the biggest rough stones of modern times. Lesedi La Rona means Our Light in Botswana’s Tswana language. The story begins with a 1,109 carat rough diamond discovered in Botswana in 2015, recognised as one of the biggest diamonds ever found in modern times for gem quality rough.

The rough was purchased in 2017 for $53 million and, after extensive cutting, produced the 302.37 carat square emerald cut diamond now known as the Graff Lesedi La Rona. The original rough also yielded dozens of additional diamonds.

It is not the biggest diamond ever found overall, and it does not need that label. What makes it remarkable is what it represents within its category, and the level of precision required to finish a stone at this scale. It is a strong entry for anyone searching for the most costly diamond, world costly diamond, or biggest diamond ever found in modern headlines.

What Makes Diamonds So Valuable

When people search for the most expensive diamond in the world, they usually expect a single neat answer and a neat price tag. The truth is a bit messier. Some stones are priceless because they are locked into royal collections or museums, so the market never gets a real chance to price them. Others have confirmed prices because they were sold at auction, where the numbers are public and final. That is why lists like this mix hard sale figures with widely cited estimates.

Decoding Diamond Values

A quick note on the numbers, because it matters. Auction prices are public and fixed, usually quoted in US dollars even when the sale happens in Hong Kong or Geneva. Estimates for crown and museum diamonds are different. They are built from insurance figures, comparable stones, historical importance, and a lot of informed guesswork. That is why you will see ranges for some pieces rather than a single neat total. It is also why the costliest diamond in the world is sometimes described as priceless.

Why Coloured Diamonds Break Records

You will notice that several of the biggest figures on this list belong to coloured diamonds, especially vivid pink and vivid blue. Those colours occur because of tiny quirks in a diamond’s formation, so supply is naturally limited. When a stone combines strong colour with a respectable carat weight and high clarity, it becomes a rare overlap of three problems solved at once. That is why auction rooms can get so intense so quickly, there might not be another comparable example for years. This is also why the most rare diamond stones often compete with the biggest diamonds on price, even when the carat weight is far smaller.

Timeless Value

A Diamond is Forever still lands because it is basically true in the ways that matter. Diamonds last physically, but they also last in the imagination, and if you like seeing how scarcity drives prices across different luxury categories, the 10 most expensive perfumes in the world is a fun comparison. Some of the stones above became famous because they were worn by royalty, some because they sit in museums, and some because they smashed records at auction as a modern highest price diamond headline.

Either way, the most expensive diamond in the world conversation always lands in the same place. The highest value diamonds sit at the intersection of geology, craftsmanship, rarity, and human history. The price tags are eye watering, but the real reason people remember these stones is simpler, they feel like time made visible.

One last thing, these rankings can shift. Exchange rates move, fresh discoveries appear, and the appetite for certain colours rises and falls. Still, the top tier stones tend to stay top tier, because rarity at this level does not come around often at all. That is what keeps the costliest diamond in the world debate alive, and why the most valuable diamond in the world is not always the one with the biggest carat number.