Where blue diamonds are made

If you search in this blog with the word "diamond", you'll find that I've written a few posts about diamonds, particularly big ones.  Ever since a young age I've had a fascination for gemstones, particularly large ones, and the history of large diamonds has been interesting to me.  That's one reason that I'm curious if they'll be able to cut one of the new large white diamonds recently discovered into a gem larger than the Cullinan I in the scepter of the British Crown Jewels.

But it's not all about size and value.  Part of the fascination is their rarity, and how they are formed, deep in the Earth (under a lot of pressure, of course).   Well, science has now determined where and how deep the very rare blue diamonds are formed.  As you might expect, it's very deep in the Earth's subsurface layers.

Rather than try to explain, I'll link to an article and excerpt from it. If you're curious, the blue color comes from traces of boron.

How Rare Blue Diamonds Form Deep below the Ocean Floor
Minerals and elements are recycled in Earth’s mantle to form the precious gems

So where are they formed, you must be wondering?

"Over the course of hundreds of millions to billions of years, the seafloor absorbs boron. As the floor becomes older and colder, it eventually becomes denser than the mantle beneath it and sinks. “It’s like a continuous conveyor belt that just keeps going for hundreds of millions of years,” says Lars Stixrude, head of Earth sciences at University College London who was not involved in the research. The boron, encompassed by rock that protects the mineral from the mantle’s high pressure and heat, continues on its path hundreds of miles downward until it reaches the lower mantle. There, the environment has such intense levels of heat and pressure that it melts boron’s protective rock sheath. Here in this deep-Earth pressure cooker, blue diamonds form. The process can take hundreds of millions of years—and that does not include the hundreds of millions of years the diamonds take to travel to the surface via volcano-like burrows called kimberlites (known to most as mines)."

So that's how.  Now that we've settled that, let's have a little fun.

The blue diamond shown above, called "The Heart of the Ocean", was featured in the movie Titanic.  It is not real.  Kate Winslet, luckily and happily, certainly is.

What you may not know is that there really was an expensive blue diamond on a necklace on the Titanic.  And it still exists.

The True Story Behind Titanic's "Heart Of The Ocean" Diamond Necklace!

It is a fascinating story.  And here's what the real gemstone and necklace look like:

It needs a name

The article doesn't say how big this blue diamond is. My guess is about 10 carats.














So now you know the rest of this story.