The Cullinan Diamond: World’s Largest Gem & Its $2 Billion Secret
Imagine holding a diamond so enormous it weighed more than a baseball. That’s exactly what happened on January 26, 1905, when mine superintendent Frederick Wells spotted something glinting in the wall of South Africa’s Premier Mine—a discovery that would rewrite gemstone history forever.
The Cullinan Diamond wasn’t just big. At 3,106 carats (about 1.37 pounds), it was and remains the largest gem-quality rough diamond ever discovered. To put that in perspective, it was three times larger than any diamond found before it and so massive that people initially thought it must be a fake.
But this extraordinary stone’s story doesn’t end with its discovery. What happened next reads like a royal thriller: a daring ocean voyage with decoy ships, cutting decisions that made master jewelers nervous, and the transformation of one massive stone into nine major gems now worn by British royalty including two stones that sit in the Crown Jewels today.
In this comprehensive guide, we’ll explore every facet of this legendary gem. You’ll understand the true Cullinan diamond size and why it remains unmatched. You’ll see how the Cullinan diamond vs Kohinoor comparison reveals fascinating differences. And you’ll discover the astonishing Cullinan diamond worth in today’s market.
The Discovery That Changed Gemstone History
Frederick Wells was making his evening rounds 18 feet below the surface at Premier Mine when the setting sun caught something reflecting in the mine wall. Walking closer, he spotted what appeared to be a large piece of glass embedded in the rock.
Wells pried it out with his pocket knife, expecting nothing more than a curious crystal. What he held instead was the largest diamond fragment ever found so large that experts believe it was only part of an even more massive crystal that had broken apart naturally over geological time.
Initial Skepticism and Authentication
The diamond measured approximately 10.1 cm × 6.35 cm × 5.9 cm (about 4 inches × 2.5 inches × 2.3 inches) roughly the size of an adult man’s fist. It weighed an astounding 3,106.75 carats in its rough state.
Many thought it was too large to be real. South African newspapers initially reported it as a probable hoax. Only after rigorous testing by multiple gemologists was its authenticity confirmed this was not only genuine but represented the finest quality diamond ever found at that size.
The diamond was named after Sir Thomas Cullinan, who opened the Premier Mine in 1902. Frederick Wells received a $10,000 reward for his find, though the stone’s value was already in the millions.
The Journey to England: A Brilliant Deception
The Transvaal government purchased the diamond for £150,000 and decided to present it as a gift to King Edward VII. But how do you safely transport the world’s most valuable object halfway around the world?
British authorities created an ingenious plan:
The decoy: A diamond (supposedly the Cullinan) traveled via steamship with armed guards, locked safes, and extensive media coverage.
The reality: While everyone’s attention focused on the heavily guarded ship, the actual Cullinan Diamond was sent via ordinary registered parcel post, simply wrapped in brown paper.
This “hiding in plain sight” tactic worked perfectly. The diamond arrived safely at Buckingham Palace on November 9, 1907 the King’s 66th birthday.
Cullinan Diamond Size: Understanding the Colossal Proportions
To truly appreciate the Cullinan, you need to understand just how extraordinarily large it was. The Cullinan diamond size in its rough state remains unmatched over a century later.
The Raw Numbers
- Weight: 3,106.75 carats (621.35 grams / 1.37 pounds)
- Dimensions: 10.1 × 6.35 × 5.9 cm (4.0 × 2.5 × 2.3 inches)
- Color: Exceptional white (colorless)
- Clarity: Remarkably clean for its size
- Classification: Type IIa (less than 2% of all diamonds)
Putting the Size in Perspective
Weight equivalents:
- About the same weight as 10-12 wedding rings
- Heavier than two golf balls combined
- The weight of about 15,000 one-carat diamonds
Historical context:
- 3× larger than the previous record holder (Excelsior Diamond at 995.2 carats)
- More than 6× larger than the Koh-i-Noor in its original form
- Larger than all previously known major diamonds combined
Evidence of an even larger stone: One side showed a smooth cleavage surface, suggesting the Cullinan broke from an even larger crystal—possibly 6,000+ carats. The other half has never been found.
After Cutting: The Nine Major Stones
The rough Cullinan was cut into nine major stones and 96 smaller brilliants, with a combined weight of approximately 1,055 carats—meaning about 66% was lost to cutting (typical for large rough diamonds).
The nine major stones:
- Cullinan I: 530.2 carats (largest clear-cut diamond in the world)
- Cullinan II: 317.4 carats
- Cullinan III: 94.4 carats
- Cullinan IV: 63.6 carats
- Cullinan V: 18.8 carats
- Cullinan VI: 11.5 carats
- Cullinan VII: 8.8 carats
- Cullinan VIII: 6.8 carats
Cullinan IX: 4.39 caratsLorem ipsum dolor sit amet, consectetur adipiscing elit. Ut elit tellus, luctus nec ullamcorper mattis, pulvinar dapibus leo.
The High-Stakes Cutting: Joseph Asscher’s Nerve-Wracking Task
What do you do with the world’s largest diamond? This question tormented experts for years. Cutting it involved enormous risk—one mistake could shatter the entire stone into worthless fragments.
The Man Who Dared
After extensive study, the task went to Joseph Asscher of Amsterdam’s renowned Asscher Brothers diamond firm. He spent six months studying the stone, mapping internal inclusions and cleavage planes, and practicing on models.
February 10, 1908: The Moment of Truth
Asscher placed a specially designed cleaving knife into a pre-cut groove and struck it with a small mallet.
The result? The blade shattered.
Terrified but undeterred, Asscher repositioned his tools and tried again. This time, the diamond cleaved perfectly along the intended plane. According to legend, Asscher fainted immediately after—though this may be embellished, the psychological pressure was certainly immense.
The complete cutting process took three years (1908-1910), ultimately creating the nine major stones plus 96 smaller brilliants. The 66% weight loss was intentional—maximizing beauty and brilliance over preserving raw weight.
Cullinan Diamond vs Kohinoor: A Tale of Two Legends
Both diamonds rank among history’s most famous gemstones, but the Cullinan diamond vs Kohinoor comparison reveals dramatic contrasts.
Size: No Contest
Cullinan (rough): 3,106.75 carats Koh-i-Noor (estimated original): ~180-190 carats Koh-i-Noor (current): 105.6 carats
The verdict: The Cullinan was approximately 17 times larger than the Koh-i-Noor’s original size and nearly 30 times larger than its current form.
Quality and Color
Both are exceptional Type IIa diamonds (the rarest category), but the Cullinan’s combination of massive size and remarkable clarity was unprecedented. Finding such purity in a 3,000+ carat stone is extraordinarily rare.
Historical Journey
Cullinan:
- Discovered 1905 in South Africa
- Clear documentation from discovery to present
- Transferred peacefully from South Africa to British Crown
- Modern colonial period
Koh-i-Noor:
- Likely 13th-14th century origins in India
- Centuries of ownership across multiple empires
- Multiple violent conquests and forced transfers
- Highly contested ownership with claims from India, Pakistan, Iran, and Afghanistan
Cutting and Transformation
Cullinan: Strategically divided into 9 major stones as planned to create multiple royal jewels
Koh-i-Noor: Reluctantly recut in 1852 from ~186 carats to 105.6 carats (43% loss) to satisfy Victorian tastes—now considered controversial
Current Location
Both reside in the Tower of London’s Crown Jewels, though:
- Cullinan I & II: Crown Jewels (public display)
- Cullinan III-IX: Royal Family’s personal collection (occasionally worn)
- Koh-i-Noor: Queen Mother’s Crown (public display)
Political Controversy
Cullinan: Moderate controversy; occasional discussions about returning to South Africa
Koh-i-Noor: Highly controversial with ongoing diplomatic tensions and formal repatriation requests from multiple countries—symbolizes colonial exploitation
Value Comparison
The Cullinan fragments combined likely exceed the Koh-i-Noor’s estimated $400-600 million value, primarily due to Cullinan I’s extraordinary 530.2-carat size. However, both are essentially priceless and cannot be sold.
Cullinan Diamond Worth: The $2 Billion Question
What is the Cullinan diamond worth in today’s market? This question fascinates gemstone enthusiasts worldwide.
Insurance Estimates
Cullinan I (530.2 carats):
- Conservative: $400-500 million
- Optimistic: $1-2 billion
Cullinan II (317.4 carats):
- Conservative: $200-300 million
- Optimistic: $600-800 million
Cullinan III-IX combined:
- Conservative: $100-200 million
- Optimistic: $300-400 million
The 96 smaller brilliants:
- Conservative: $50-100 million
- Optimistic: $100-150 million
Total combined estimates:
- Conservative: $750 million – $1 billion
- Optimistic: $2 billion – $3.5 billion
Why Valuation Is Challenging
Legal impossibility: The Cullinan fragments belong to the British Royal Family and cannot legally be sold under British law.
No comparisons exist: For context, the largest diamond ever auctioned was the Pink Star (59.60 carats) at $71.2 million. Cullinan I is nearly nine times larger.
Historical premium: Royal provenance and historical significance add incalculable value beyond just physical properties.
If Discovered Today
If the 3,106-carat rough Cullinan were discovered today:
- Pre-auction estimate: $500 million – $1 billion
- Expected sale price: $1.5 billion – $3 billion
- Potential with competitive bidding: $3-5 billion
However, finding a buyer willing to spend $3+ billion on a diamond would be extremely difficult, potentially requiring division into smaller stones.
The Priceless Factor
Ultimately, the Cullinan’s worth exceeds any monetary figure because of:
- Historical irreplaceability
- Connection to British royalty and 20th-century history
- Scientific importance (evidence of extraordinary geological conditions)
- Cultural and educational value to millions worldwide
Like the Crown Jewels collectively, the Cullinan fragments are effectively priceless.
Where to See the Cullinan Diamonds Today
Tower of London (Public Display):
Cullinan I (Great Star of Africa) – Mounted in the Sovereign’s Sceptre with Cross Cullinan II (Second Star of Africa) – Set in the Imperial State Crown
Visitor Information:
- Address: Tower of London, London EC3N 4AB, UK
- Hours: Typically 9:00 AM – 5:30 PM (varies seasonally)
- Admission: £33-35 adults (check official website)
- Best times: Weekday mornings or late afternoons
Royal Family Personal Collection:
Cullinan III through IX belong to the Royal Family’s personal property and are occasionally worn at state functions but not on permanent public display. Queen Elizabeth II frequently wore several of these stones, and they continue to appear at royal events.
Frequently Asked Questions About the Cullinan Diamond
1. How big is the Cullinan Diamond and why is it famous?
The Cullinan Diamond weighed an extraordinary 3,106.75 carats (1.37 pounds) in its rough state, making it the largest gem-quality diamond ever discovered. The Cullinan diamond size was approximately 10.1 × 6.35 × 5.9 centimeters—about the size of an adult’s fist. It was discovered in South Africa on January 26, 1905, and was so large people initially thought it was fake. The diamond is famous for its record-breaking size combined with exceptional quality—it was remarkably clear and colorless despite its massive dimensions. After cutting, it yielded nine major stones (the largest being 530.2 carats) plus 96 smaller brilliants, with the two largest now in the British Crown Jewels.
2. What is the Cullinan Diamond worth today?
The Cullinan diamond worth is estimated conservatively at $750 million to $1 billion for all fragments combined, with optimistic estimates reaching $2-3.5 billion. Cullinan I alone (530.2 carats) is valued at $400 million to $2 billion. However, the diamond is essentially priceless because it cannot legally be sold—it belongs to the British Crown Jewels and Royal Family. For comparison, the largest diamond auctioned was the Pink Star at 59.60 carats for $71.2 million, and Cullinan I is nearly nine times larger. If the original rough stone were discovered today, experts believe it could sell for $1.5-5 billion, making it the most valuable gemstone in history.
3. How does the Cullinan Diamond compare to the Koh-i-Noor?
The Cullinan diamond vs Kohinoor comparison shows dramatic differences. The Cullinan was approximately 17 times larger than the Koh-i-Noor’s estimated original size (3,106 carats vs. ~180-190 carats) and 30 times larger than its current 105.6 carats. Both are exceptional Type IIa diamonds, but the Cullinan’s combination of massive size and clarity was unprecedented. Historically, the Koh-i-Noor has a complex 700-year journey through conquest and war, while the Cullinan has straightforward 20th-century provenance. The Koh-i-Noor faces intense repatriation claims from multiple countries, while the Cullinan generates less controversy. In value, the Cullinan fragments combined significantly exceed the Koh-i-Noor’s estimated $400-600 million worth.
4. Where can I see the Cullinan Diamonds?
The two largest Cullinan Diamonds are on public display at the Tower of London’s Crown Jewels exhibition. Cullinan I (530.2 carats) is mounted in the Sovereign’s Sceptre with Cross, while Cullinan II (317.4 carats) is set in the Imperial State Crown. These can be viewed year-round during Tower of London hours (typically 9:00 AM – 5:30 PM, admission around £34). The remaining seven major stones (Cullinan III-IX) belong to the Royal Family’s personal collection and are occasionally worn at state functions but aren’t on permanent display. Your best opportunity to see the largest Cullinan fragments is at the Crown Jewels exhibition in London.
5. What happened during the cutting of the Cullinan Diamond?
The cutting was one of the most high-stakes operations in gemstone history. Joseph Asscher of Amsterdam’s Asscher Brothers studied the diamond for six months before attempting the first cleave on February 10, 1908. His first attempt shattered the steel blade rather than splitting the diamond. The second attempt succeeded perfectly. According to legend, Asscher fainted from relief afterward. The complete process took three years (1908-1910) and created nine major stones ranging from 530.2 carats to 4.39 carats, plus 96 smaller brilliants. About 66% of the rough diamond’s weight was lost—typical for large stones where brilliance takes priority over weight. The resulting stones’ combined value far exceeded what the uncut rough would have been worth.
Conclusion: The Cullinan’s Enduring Legacy
The Cullinan Diamond stands as nature’s most spectacular demonstration of what’s possible when perfect geological conditions persist for billions of years. From its dramatic 1905 discovery to its current status in British royal collections, this extraordinary stone has captivated the world like no other gemstone.
The Cullinan diamond size—at over 3,100 carats in rough form—still dwarfs every gem-quality diamond discovered since. When comparing the Cullinan diamond vs Kohinoor or any other famous gemstone, the Cullinan’s combination of massive proportions and exceptional quality remains unmatched. And while the Cullinan diamond worth ranges from $1 billion to $3.5 billion, its true value transcends money—it represents geological rarity, master craftsmanship, royal heritage, and natural wonder combined in one irreplaceable treasure.
The nine major stones that resulted from cutting the original rough now serve different purposes—Cullinan I and II as symbols of sovereign authority displayed for millions to admire, while the smaller fragments add sparkle to royal appearances and connect modern royalty to this legendary discovery.
Perhaps most remarkably, evidence suggesting the Cullinan was only part of an even larger crystal raises tantalizing questions: where is the other half? Could an even more spectacular discovery await somewhere on our planet? While unlikely, the possibility adds intrigue to this already extraordinary story.
Ready to witness this legendary gemstone yourself? Plan your visit to the Tower of London to see Cullinan I and II sparkling in the Crown Jewels exhibition. The Great Star of Africa awaits—proving that some treasures truly are worth their weight in diamonds.
Read More: Hope Diamond Exposed: The Curse, Secrets & $250 Million Mystery
