Jewelry Blog

The Complete History of the Cullinan Diamonds

Cullinan Diamond Crown Jewels

The story about the biggest diamond ever found doesn’t cease to impress us, even though it happened more than a century ago. We’re talking about the Cullinan diamonds, a set of diamonds larger than a human fist. Rumor has it that it’s only a fragment of an even larger diamond, but, for now, we don’t have any proof of that. 

The gem cutters divided the Cullinan diamond into nine smaller stones, and each of them has a fascinating history. Today, most of them belong to the British royal family and you can see some of them in the museum.

Discovery of the Cullinan Diamonds


Cullinan Sign

Like many great things, the Cullinan diamond discovery came about accidentally in 1905. Frederick Wells, the mine supervisor, was making a routine inspection trip to the Premier Mine in South Africa. The Premier Mine belonged to Sir Thomas Cullinan and his family. It was a prolific mine, but nobody expected something like this. 

Frederick Wells noticed a shiny object a few feet above him. When he got closer, he thought that he found a massive piece of glass. When they uncovered it, they realized that it was a giant diamond. It was 4″ long, 2.5″ wide, and 2.3″ deep. The world had never seen a diamond that looks like this before. They had to contact experts to make sure they weren’t wrong. 

When they weighed it, it turned out to be the heaviest diamond on Earth, with its 3106 carats (621g). For two years, Sir Thomas Cullinan couldn’t decide what to do with the diamond. They exhibited it in Johannesburg, and more than 8,000 visitors came to see this miracle. You can still see a replica of this diamond in the Cape Town Diamond Museum. 

The Cullinan family had one problem though. They had to deal with so many people who wanted to search their mine. There were rumors that this giant diamond was only a part of an even bigger gemstone. Although this could be true, there is still no proof of this theory. 

A Gift to King Edward VII 

Who could care for the biggest diamond better than the royal family? So, when the Transvaal Colony government offered to buy a diamond as a gift for King Edward VII, Sir Thomas Cullinan immediately accepted the offer. He sold the diamond on 17 October 1907, for £150,000. If that doesn’t sound like a lot to you, let me explain that it’s equivalent to £15 million today. 

King Edward VII got the Cullinan diamond as a gift for his 66th birthday. He organized a big party, and members from all the European royal families came to see it. The diamond was much more than a simple birthday gift. It was a symbolic gesture of goodwill, after the Boer War and tensions between Britain and South Africa. 

We believe that even the King couldn’t have remained indifferent after receiving a spectacular gift like that. 

Cutting of the Cullinan Diamonds 

Cullinan Diamond Crown Jewels

The Cullinan diamond was too big, and it wasn’t possible to put the whole diamond in a crown or any other piece of jewelry. The only solution was to cut it. That’s why King Edward VII ordered to send the diamond to the Royal Asscher Diamond Company in Amsterdam. 

The Asscher’s had a long family tradition of gem cutting for the royal family and other celebrities. They were the most reliable company of their time, and they already had experience with big diamonds, such as the Excelsior diamond. With its 997 carats (199g), the Excelsior diamond was the largest diamond ever found. However, that was before the Cullinan diamond. 

Can you imagine being given the task to split the world’s largest diamond? Imagine how Joseph Asscher must have felt. He spent weeks thinking about the best way to do it. Then, he spent days preparing his equipment. The first attempt was a disaster. The Cullinan diamond was so strong that the knife broke, and the diamond remained unchanged. 

However, Joseph Asscher managed to cut the Cullinan diamond into two pieces. Witnesses claimed that he was so relieved that he fainted right after cutting the diamond. After that, it took him eight months to cut and polish nine pieces. 

He named them Cullinan I, Cullinan II, and so on, and we still know them by those names today. Cullinan I is the largest, Cullinan II is the second-largest, and so on. But that’s not all. There were also 97 smaller stones, that are now all around the world. Joseph Asscher also left some unpolished fragments, 19.5 carats in total. All that from only one large diamond! 

What Happened with the Cullinan Diamonds? 

The two largest diamonds, Cullinan I and Cullinan II, were a gift to King Edward VII. The royal family allowed the Asscher Diamond Company to keep the smaller gems as a reward for the great job they did. However, the royal family later purchased other pieces from the Asscher family. Today, you can see them in the Tower of London, as a part of the Crown Jewels. 

The royal family likes to call Cullinan I The Star of Africa. With its 530 carats, it’s still one of the biggest diamonds, and it’s the largest clear-cut diamond in the world. King Edward placed it in the Sovereign’s Royal Scepter, which had to be adjusted to accommodate such a big stone safely. 

Cullinan II also has another name – the Second Star of Africa. With its 317 carats, it’s one of the most impressive diamonds ever. You can see it in the Imperial State Crown’s front, bellow the Black Prince’s Ruby. Each monarch wears this crown when leaving Westminster Abbey after their coronation. They sometimes wear it on some other special occasions too. 

What About the Rest of Diamonds? 

Cullinan Diamonds

The other stones are considerably smaller, and none of them has more than 100 carats. However, their value is also enormous. Queen Mary ordered to put Cullinan III in the crown used for her coronation. She also ordered to design various brooches and jewelry with the remaining diamonds. 

Today, we most often get to see Cullinan III and Cullinan IV. Queen Elizabeth II loves to wear them together as a brooch. You can also see members of the royal family wearing smaller Cullinan diamonds on special occasions. 

No one can tell for sure what happened with all the 97 smaller stones. While the royal family owns the nine biggest Cullinan diamond, others are in the possession of the world’s richest families. Even though they’re not as significant as the main Cullinan diamonds, imagine what it feels like to have a part of the same diamond that the Queen wears. 

The Largest Diamond Ever Found 

After more than 100 years, there’s no larger or more impressive diamond than the famous Cullinan. It’s incredible to think that a mine supervisor discovered it merely by accident. If it hadn’t been for him, the Cullinan diamond would probably still be lying under the ground, as it did for more than a billion years. 

Who knows whether there are even bigger diamonds beneath the Earth’s surface today? For now, we haven’t discovered them, but it doesn’t mean that someone won’t find them, just like what happened with the Cullinan. 


About Benjamin Khordipour

Benjamin Khordipour is one of the jewelry researchers and gemologists at Estate Diamond Jewelry. He received his official gemological degrees from both the GIA and GUBELIN. He also regularly contributes to Business Insider, Forbes, Rapaport, CNBC, and Brides Magazine. Benjamin was born in New York and joined Estate Diamond Jewelry in 2014. He is passionate about vintage jewelry and diamonds. This blog was built on his strong belief that jewelers have a responsibility to properly educate their customers. In 2019, Benjamin co-authored the book The Engagement Ring Guide for Men. His favorite vintage jewelry era is the Art Deco Era and his favorite type of stone is the Kashmir Sapphire. He also collects rare antique pins.