The Cullinan I: Your Guide to the 3rd Largest Diamond in the World

The Cullinan I, also known as the Great Star of Africa, is the third largest cut diamond in the world. It's not just a gem; it's a piece of history, a political symbol, and one of the most heavily guarded objects on the planet. Sitting at 530.4 carats, it's a drop-cut brilliant stone that forms the head of the Sovereign's Sceptre with Cross in the British Crown Jewels. If you've ever searched for "world's largest diamonds," you've likely seen its name. But most articles just list its weight and move on. Having spent years studying gemology and visiting collections, I find the real story—and the practical details of seeing it—are often glossed over. Let's fix that.

What Exactly Is the Cullinan I Diamond?

Let's get the numbers straight. When people talk about the "largest diamonds," they usually mean faceted, polished stones, not rough, uncut ones. The Cullinan I holds the #3 spot in that specific category. It's crucial to make this distinction because the largest rough diamond ever found was also a Cullinan—the Cullinan rough, at 3,106 carats. That massive stone was cut into nine major gems (Cullinan I to IX) and 96 smaller brilliants. The Cullinan I is the biggest of those nine.

Here’s how it stacks up against the top two, which are often confused.

The cut is a masterclass in risk-taking. Joseph Asscher, tasked with cleaving the original Cullinan in 1908, reportedly fainted after the first successful blow. They weren't just cutting a stone; they were dividing a historic, gift-of-state. The pear shape was chosen to preserve as much weight as possible while creating a stone fit for a monarch's sceptre.

From Rough Stone to Royal Sceptre: The Cullinan's Story

The diamond was discovered in 1905 at the Premier Mine in South Africa. It was named after the mine's chairman, Thomas Cullinan. The Transvaal government, then a British colony, purchased the stone and presented it to King Edward VII in 1907 as a birthday gift—a move seen by many as an attempt to smooth over post-Boer War tensions.

This is where the first non-consensus point comes in. Many sources call it a "gift." In the context of colonial power dynamics, it's more accurate to view it as a tribute or a strategic political offering. The stone's journey from South African soil to the British crown remains a point of contention and is essential to understanding its modern symbolic weight.

The cutting, as mentioned, was entrusted to Amsterdam's Asscher Brothers. The process took months. The first cleave alone required weeks of planning. They created the two largest stones, Cullinan I and II (the 317-carat Cullinan II, in the Imperial State Crown), along with the seven other major stones. All were gifted to the British royal family. A persistent myth says the smaller stones were "payment" to Asscher, but they were, in fact, retained and later sold by the Transvaal government. The royals eventually bought Cullinan III and IV.

Cullinan I was set into the Sovereign's Sceptre with Cross in 1910, replacing a previous, smaller stone. It's designed to be removable and has been worn separately as a brooch by queens. It has been used in every coronation since George V in 1911.

The Day I Saw It (And What They Don't Tell You)

I visited the Tower of London on a grey Tuesday. The queue for the Jewel House was long, but it moves. The first thing that strikes you is the security—thick bulletproof glass, low lighting, and a moving walkway that (let's be honest) rushes you past a bit too quickly. You get a good 30-45 seconds in front of the sceptre.

Here's what most guides won't say: The diamond doesn't "blaze" or "sparkle" under the museum lights as you might imagine. The setting is ornate gold, and the glass is thick. The awe comes from knowing its history and its sheer, silent weight. It looks less like a Hollywood prop and more like an artifact of immense, quiet power. It's humbling, not dazzling. Plan to go around the display twice if you can.

Where and How Can You See the 3rd Largest Diamond?

The Cullinan I is on permanent public display in the Jewel House at the Tower of London. This isn't a temporary exhibition; it's been there for decades. But you need a plan.

The Crown Jewels collection, including the sceptre, is housed in a vault-like room with those moving walkways. Photography is strictly prohibited inside the Jewel House. Be prepared for airport-level security screening upon entry to the Tower grounds.

Is it worth it? For anyone interested in history, gems, or power, absolutely. You're not just seeing a big diamond; you're seeing one of the most potent symbols of the British monarchy, housed in a fortress with 1,000 years of its own brutal history. The context is everything.

Beyond the Size: Ownership, Value, and Modern Context

You can't talk about the Cullinan diamonds without addressing the elephant in the room: calls for repatriation. Following Queen Elizabeth II's death in 2022, there has been renewed public debate in South Africa about the return of the Cullinan stones. Petitions and media discussions frame them as colonial spoils. The UK government and Royal Collection Trust maintain they were a "legal gift."

This tension adds a complex, modern layer to viewing the stone. It's not just a beautiful object; it's a focal point for ongoing conversations about colonial history and restitution.

What's it worth? It's effectively priceless. Insured? Certainly. But it would never be sold. Its value is historic, symbolic, and institutional. If you forced an appraisal for insurance, experts suggest a figure in the high hundreds of millions of dollars, but such a number is almost meaningless. Its true "value" is in its role as an inalienable asset of the British state.

From an economic perspective, it's a non-liquid, ultra-high-value asset that contributes to the cultural capital and tourism economy of the UK. The Tower of London draws millions of visitors a year, with the Crown Jewels as the top attraction.

Your Questions About the Cullinan I Answered