I did have a couple of paragraphs of lead up to that, but honestly, if you're just here to find out what the most expensive object in the world by weight is, it's this stamp.

There's now gonna be several diversions about why it should count as that, what the alternatives might be, and why it's that expensive.

But if you just clicked the video to find out the answer to the question in the title, it's this stamp.

$8.3 million for about forty milligrams.

The stamp's called the British Guiana one cent magenta.

It's the absolute pinnacle of rarity in stamp collecting.

It's not a variant. It's not a watermark variety. It's not a printing error.

It's a straight, normal postage stamp of which only one survived, and that's what makes it unique.

So this was actually produced at the local printer office, so it was only ever intended to tide the colony over for a week or two.

This one-cent stamp also, it's believed, only paid a newspaper rate, which meant that they were used just to post newspapers locally, and newspapers, even back then, were immediately disposable.

There may be more expensive stuff by weight.

Antimatter is often called the most expensive stuff in the world, but I don't think that should count here for several reasons.

First, there's no way for anyone, no matter how wealthy they are, to buy a gram of antimatter in the shops or at auction.

Second, substances aren't objects.

The English language has a distinction between "count nouns" and "mass nouns".

It's the difference between "there was a dog on the road" and "there was dog on the road".

There's probably a less gruesome way of explaining that, but I guarantee that's gonna stay in more people's heads.

And the third reason: this stamp is non-fungible.

Even if there was an antimatter shop just down the road...

okay, let's let's go for something more realistic, but also very expensive.

Let's say there's a shop selling printer ink just down the road.

One gram of printer ink is the same as any other gram.

They're fungible. If you switch them out, it doesn't matter.

This stamp is non-fungible, not just because it's the only one left, but because of its history.

It's a unique object.

The stamp was actually first discovered in 1873 by a 12-year-old schoolboy.

Now, at the time it would have been nothing unusual, because over time, multiple stamps of everything else were discovered.

But this is the only stamp in British Commonwealth history where no other examples have ever turned up.

It passed through an increasingly prestigious list of the greatest names in philatelic history.

Stanley Gibbons is the world's oldest stamp dealership.

We have an auction house, two retail teams, and a coin company called Baldwins.

Stanley Gibbons was lucky enough to purchase the stamp at auction in New York.

And now it's on display every Monday, Wednesday, and Friday, just for conservation and light reasons, but indefinitely here in an oxygen-free conservation case.

This stamp has repeatedly set the record for most expensive, and every time it does, it adds another line to its already very long history.

It's expensive because it's rare.

Yes, there is only one of these in the world, and the way our society works, someone's got to own it.

But outside stamp collector circles, not many people would care about "the rarest stamp".

But to the wider world, it's famous because it's expensive, and more fame will likely make it more expensive.

And I guess I'm helping that cycle continue by making this video about it.

I wouldn't claim to know the company's motivations, but I'd suspect that it's on display to the public here,

at least in part, because the company is selling shares in it, and more fame will help it keep or raise its value.

This is not an endorsement, by the way. I approached them about filming. They've not paid me. I have no desire to buy or sell a share in a stamp.

But if you want to challenge this for "the most expensive object in the world by weight", and take the very, very tiny crown,

well, the first step would be finding something even lighter than forty milligrams, but just as historic and just as non-fungible.

Good luck.