What Is The Most Expensive Diamond In The World

Picture this: a few years ago, I’m at a friend’s house, and she pulls out her grandmother’s old engagement ring. It’s tiny, a little scratched, but she’s beaming. “It’s priceless,” she says, and I nod, because of course it is—sentimentally. But then she adds, “But my mom says it’s worth about two thousand bucks.” And I thought: two thousand bucks is cute, but what does really expensive look like? Like, “sell-your-house-and-still-owe-money” expensive? That’s when I fell down the rabbit hole of the most expensive diamond in the world.

Spoiler alert: it’s not a typical engagement ring sparkler. The current title-holder is the Koh-i-Noor (which means “Mountain of Light”), but hold your horses—we’re not talking about its price tag because, ironically, it’s never been sold. Yeah, you heard me. It’s technically priceless, but let’s be real: every diamond has a number, and this one’s estimated at over $1 billion. That’s billion with a B. For a single rock. (Insert dramatic pause here.)

So, what makes a diamond the “most expensive”?

It’s not just about size, though that helps. The Koh-i-Noor weighs 105.6 carats—impressive, but not even close to the largest. What makes it insane is its history and curse. Yes, curse. Legend says whoever owns it will rule the world, but also suffer terrible misfortune. (Sounds like a bad Tinder bio, right?)

It was mined in India, then passed through Mughal emperors, Persian kings, and eventually ended up in the British Crown Jewels. The British have owned it since 1850, and you can see it in the Tower of London—but India, Pakistan, and Afghanistan all want it back. So, no, you can’t buy it at a jewelry store. Sorry, Bezos.

Honorable mention: The Pink Star

If you want a diamond you can actually buy (if you’re Elon Musk), meet the Pink Star. This bad boy is a 59.6-carat, internally flawless, fancy vivid pink diamond. In 2017, it sold at auction for $71.2 million. That’s more than most people’s lifetime earnings, and it’s basically a pink pebble. But hey, context: it took 18 months to cut that stone. Imagine the anxiety.

And here’s the ironic part: the buyer, a Hong Kong jeweler, immediately renamed it the “CTF Pink Star” after his company. Because when you spend $71 million, you get naming rights. (Meanwhile, I can’t even rename my cat without a family vote.)

The Most Expensive Diamonds in the World

But wait—there’s a Cullinan in the shadows

The Cullinan Diamond was discovered in 1905 in South Africa and weighed an unfathomable 3,106 carats. That’s 1.3 pounds of diamond. You could literally throw it at a thief. It was cut into nine major stones, the largest of which is the Star of Africa (530 carats), set in the British Royal Sceptre. If you added up the value of all its pieces? Over $2 billion. But it’s not “for sale,” so it’s like that one friend who owns a yacht—cool for them, but not exactly in your Amazon cart.

Here’s my favorite part: the Cullinan was presented to King Edward VII as a gift, and the delivery was a whole James Bond-level scheme. A fake diamond was sent on a boat with detectives, while the real one was mailed in a plain box. Yeah, they literally shipped a billion-dollar rock via parcel post. (I double-checked this. True story.)

What about the Hope Diamond?

You’ve heard of it—the deep blue beauty said to be cursed. It’s worth $250 million, but it’s not the most expensive because it’s “only” 45.52 carats. Still, the curse rumor keeps it famous. Owners supposedly died, went mad, or lost fortunes. (Fun side note: one owner, Evalyn Walsh McLean, let her dog wear it for fun. The dog lived to 15. So much for the curse.)

Most Expensive Diamond Ever Sold – RATQQ

But here’s the kicker: the most expensive diamond isn’t even a single diamond anymore. In 2022, a record was set for a diamond sold at auction: the De Beers Blue, a 15.10-carat fancy vivid blue, sold for $57.4 million. That’s $3.8 million per carat. For reference, your average engagement ring diamond costs about $60,000 per carat. Do the math—it’s like buying a Ferrari per sharp corner.

So, what’s the real answer?

If we’re talking price tag, the Koh-i-Noor is the theoretical winner at over a billion, but since it’s not for sale, the Pink Star holds the public record. And if you want to be pedantic (and I do), the Cullinan’s combined pieces would smash all records—but they’re scattered across royal regalia.

Honestly, the most expensive diamond in the world might just be the one in your jewelry box that someone you love gave you. (Cheesy, I know, but it’s my blog, so I’m allowed.) But if you’re ever in London, go stare at the Koh-i-Noor in the Tower of London. It’s free. And you can whisper, “I’m not touching you, curse,” like I did. Security didn’t laugh, but I did.

Now, if you’ll excuse me, I’m off to check under my couch cushions for a billion-dollar diamond. A girl can dream, right?