Editors

5 Interesting Facts You Might Not Know About Diamonds

EditorsApr 10, 2020

5 Interesting Facts You Might Not Know About Diamonds

Editor-in-Chief Michelle Graff recaps a webinar in which she learned more about the stones’ formation, inclusions and the oldest diamonds on Earth.

20200410_552_carat_diamond_copy.jpg
This 552-carat diamond was recovered from the Diavik Mine in Canada’s Northwest Territories in 2018, and holds the title of largest diamond ever found in North America. Canada is home to the oldest diamonds on Earth.
Last week, I wrote a blog post containing a list of 10 jewelry-related movies to watch while you’re safe at home to give both myself and our readers a break from coronavirus-related news.

I had a great deal of fun doing it, and it served as a much-needed reminder of how much I like to just write, not necessarily about a controversy or a lawsuit, or with clicks in mind, but just for the sheer pleasure of finding an expressive way of sharing something I enjoy.

With that in mind, I’m having fun again this week, this time by sharing five facts about diamonds gleaned from a webinar.

On Thursday, geologist Evan Smith, a research scientist at the Gemological Institute of America, held the first in what is going to be a series of online “Knowledge Sessions” presented by GIA.

The webinars will feature presentations on gemology from scientists, field gemologists and educators, continuing next Thursday with Mike Breeding, GIA senior research scientist, talking about identification methods for lab-grown diamonds.

(GIA is currently building a web page for its Knowledge Sessions; we will share it as soon as it is available.)

Smith’s talk, “The Unique Story of Natural Diamond,” focused on what makes the hardest substance on Earth—and one of the world’s most popular gemstones—so interesting to geologists.

I’ve interviewed and written about Smith’s research here and there over the years; he was the lead author of an article on blue diamonds that landed on the cover of Nature, a scientific journal, in 2018, and his diamond research made the cover of Science in 2016.

He alluded to both these studies in his presentation and taught me a few new things about diamonds as well.

Please feel free to comment below if you’ve learned anything, or if you just feel like saying hello. You also can view the presentation in its entirety on YouTube.

1. Diamonds form deeper in the earth than other minerals.

Most minerals including corundum (ruby and sapphire) and beryl (emerald, aquamarine and morganite) form in the Earth’s crust, which is the layer upon which we all live.

But not diamond, which Smith said is “completely exotic … because it is formed much deeper in the Earth,” beneath the crust at depths of 150-200 kilometers (93-124 miles) in the base of old, thick continents.

Some go even deeper than that, forming at the boundary between the Earth’s mantle and its outer core. These are known as superdeep diamonds.

(For those needing a visual refresher on the layers of the Earth, I found this diagram to be helpful.) 

 
Smith said “very energetic” volcanic eruptions that come from below 200 kilometers bring diamonds to the surface. They are a sort of “accidental passenger” in these explosions.

With them, they carry valuable information in their mineral inclusions, which most commonly include kyanite, garnet and olivine.

Diamond inclusions can help researchers understand the distribution of elements in the Earth’s layers, for example, or when plate tectonics started.

“The diamond is surprisingly good at preserving these materials,” Smith said. “It’s very hard and durable, and good at keeping things from diffusing, or leaking, out of it, and diffusing, or leaking, into it.

 “There’s a tremendous of information trapped in these diamonds.”

2. Superdeep diamonds were completely misunderstood until a few years ago. 

For many years, diamonds that form at depths greater than 200 kilometers were believed to be small and never gem quality. 

But in the past four years, Smith said, researchers have found that many large, high-quality diamonds—Type IIa diamonds (stones with top color and clarity) and Type IIb diamonds, which are gray or blue because of the presence of boron—are actually superdeep stones. 

Evan Smith and a team of researchers studied offcuts from Type IIa diamonds, like this 404-carater, to gain a better understanding of the elements in Earth’s deep mantle. Their research landed them, and this diamond, on the cover of Science magazine in 2016.
Evan Smith and a team of researchers studied offcuts from Type IIa diamonds, like this 404-carater, to gain a better understanding of the elements in Earth’s deep mantle. Their research landed them, and this diamond, on the cover of Science magazine in 2016.

One example of a superdeep diamond is the 404-carat rough diamond recovered from the Lulo Mine in Angola in 2016 (pictured above). Immediately found to be Type IIa and D color, it was the biggest diamond ever known to come from Angola.

The 813-carat Constellation diamond from the Karowe mine in Botswana also is a superdeep diamond, as is the famous Hope diamond and, of course, the largest diamond ever found, the 3,106-carat Cullinan.

Smith said superdeep diamonds are identifiable by the presence of high-pressure mineral inclusions like Ca-pv, calcium perovskite.

3. There are more diamond types than you might think.

Generally, when we talk about diamond types in the trade, we think of Type IIa or Type IIb, terms that speak to a diamond’s physical appearance, its color and clarity and, thereby, its value.

But to geologists like Smith, there are also eclogitic and peridotitic diamonds, two terms I had never heard prior to Thursday’s lecture.

Peridotite and eclogite are two types of rock found in the Earth’s mantle, and diamonds can form in both. These are not superdeep diamonds but the ones found closer, relatively speaking, to the surface of the Earth, also known as lithospheric diamonds.

Peridotite is an igneous rock and is the predominant rock type found in the mantle. If researchers find olivine inclusions in a diamond, then it tells them the host rock was peridotite.

A metamorphic rock, eclogite is much less common. The presence of kyanite inclusions in a diamond indicates it formed in eclogite rock.


In 2018, Smith and a group of researchers completed a two-year study on included blue diamonds, like this 3.81-carat stone, that shed lights on how and where blue diamonds form. It was featured on the cover of Nature. (Photo credit: Robison McMurtry © GIA)
In 2018, Smith and a group of researchers completed a two-year study on included blue diamonds, like this 3.81-carat stone, that shed lights on how and where blue diamonds form. It was featured on the cover of Nature. (Photo credit: Robison McMurtry © GIA)

4. The oldest diamonds in the world are found in Canada.

Smith’s presentation included a timeline (who doesn’t love a timeline?) that illustrated just how old diamonds are relative to the history of, well, everything. 

The Earth dates back 4.5 billion years while the planet’s oldest rocks, found in Northern Quebec, are 4.3 billion years old. 

The oldest diamonds follow at 3.5 billion years old and, like the Earth’s oldest rocks, come from Canada, a fact I already was aware of after hearing Karen Smit, another GIA research scientist, speak about the GIA’s Diamond Origin Program back in the fall. 

Smit said the oldest diamonds studied by geologists so far have come from the Diavik mine, which Rio Tinto owns and operates in partnership with Dominion Diamond Corp. 

 Related stories will be right here … 

Some of Earth’s “younger” diamonds can be found at the Argyle (1.6 billion years old) and Ellendale mines (1.4 billion years old) in Australia, and in Sierra Leone, where the Zimmi diamonds are a spry 650 million years old.

To put this in perspective: All these diamonds are older than the Atlantic Ocean, which opened up when supercontinent Pangaea began to break apart about 200 million years ago, and the dinosaurs, which died off 65 million years old.

5. Pliny the Elder had something to say about diamonds.

Smith opened up his talk with a quote from Pliny the Elder, a Roman philosopher and naturalist who lived about 2,000 years ago: “Diamond is the most valuable, not only of the precious stones, but of all things in this world.” 

And he concluded it with a quote from himself that I liked: “Every diamond tells a story from a place we can’t go and from a time long since passed.”

I’ve now shared a Pliny the Elder quote; my week is complete. 

Have a great weekend everyone, and stay safe. 

Michelle Graffis the editor-in-chief at National Jeweler, directing the publication’s coverage both online and in print.

The Latest

Macy’s Herald Square store
MajorsJul 16, 2024
Macy’s Ends Buyout Talks

The retailer will not be making a deal with Arkhouse Management and Brigade Capital Management, opting to focus on its turnaround plan.

Crime police cars
CrimeJul 16, 2024
Thieves Nab $500K in Jewelry in Calif. Group Smash-and-Grab

The Berkeley robbery follows two other Bay Area robberies involving multiple suspects, one in May and one in June.

National Jeweler columnist Lilian Raji
ColumnistsJul 16, 2024
The PR Adviser: Awareness Starts With Your Online Store

Lilian Raji discusses the importance of having an intentional website design that aligns with your brand or store’s goals.

Untitled design.jpg
Brought to you by
The End of an Era? Lab-Grown Diamonds' Journey Towards Price Stability

As the demand for lab-grown diamond jewelry may still be increasing, the most notable change we are likely to see is price stabilization.

Catbird The Met collection
CollectionsJul 16, 2024
Catbird Debuts New Met Collection

It’s the second collaborative offering from the jewelry brand and the New York City art museum.

Weekly QuizJul 11, 2024
This Week’s Quiz
Test your jewelry news knowledge by answering these questions.
Take the Quiz
Craftsman holding Pomellato Arengario necklace
MajorsJul 16, 2024
Pomellato Acquires Valenza Setting Lab

The Kering-owned brand bought VSL to reinforce its manufacturing capabilities.

Ewa Abrams, Kering’s new president for the Americas
MajorsJul 16, 2024
Kering Appoints New President for Americas Region

The luxury conglomerate promoted General Counsel Ewa Abrams to the role, succeeding Laurent Claquin.

1872 x 1052 Gemolite.jpg
Brought to you by
Meet Gemology’s Next Generation Microscope: GIA® Gemolite® NXT Professional Edition

GIA®’s most advanced microscope has new features to optimize greater precision and comfort.

Tanzanite ring
MajorsJul 15, 2024
Signet Falls 11 Spots on NRF’s ‘Top 100’ Retailers List

The jewelry giant came in at No. 67 on the list, down from No. 56 last year.

 2025 Gem Awards logo
Events & AwardsJul 15, 2024
Nominations Are Open for the 2025 Gem Awards

Submissions in the categories of Jewelry Design, Media Excellence, and Retail Excellence will be accepted through Aug. 23.

Sunlit’s Sun Goddess Supreme Ring and Pyramid Rutilated Quartz Necklace
Events & AwardsJul 15, 2024
NY Now Expands Emerging Designer Segment for Its Summer Market

Curated at Luxury Lifestyle will build on the former initiative, the Emerging Fine Jewelry Designer Incubator.

Collage of Caitlin Albritton and her jewelry
Events & AwardsJul 15, 2024
Halstead Announces 2024 Grant Winner

Caitlin Albritton won the 19th annual Halstead Grant for emerging jewelry businesses.

Myne London
CollectionsJul 12, 2024
Myne London to Support Malala Fund

The emerald supplier will donate a percentage of sales from its “Star Power” earrings to the nonprofit in support of girls’ education.

The Jewelry Symposium logo
Events & AwardsJul 12, 2024
The Jewelry Symposium Is Looking for Speakers

TJS is seeking jewelry manufacturing and technology experts to speak at its 2025 event.

Sculptural Freeform Earrings
CollectionsJul 12, 2024
Piece of the Week: Marrow Fine’s ‘Sculptural Freeform’ Earrings

The earrings were inspired by the landscape at Joshua Tree and Jean Arp’s abstract sculptures.

Jewelers of America learning workshop Providence logo
Events & AwardsJul 11, 2024
JA to Host Next Learning Workshop in Providence

The one-day workshop will be held July 17 at the Rhode Island School of Design.

Jewelers International Showcase Logo Statue
Events & AwardsJul 11, 2024
Registration Now Open for JIS Fall 2024

The jewelry trade show will take place in Miami Oct. 6-9.

Kyle Kuzma, D’Angelo Russell, Jalen Green, Jaime Jacquez Jr., Kevin Love, Josh Hart, and Seth Curry
MajorsJul 11, 2024
David Yurman Names 7 NBA Players as Brand Ambassadors

The partnership reinforces David Yurman’s position as a leader in men’s jewelry, said the company.

U.S. Customs and Boarder Protection Paperwork
CrimeJul 10, 2024
US Customs Seizes $10M in Counterfeit Jewelry

Officers intercepted three packages within 24 hours containing fake goods claiming to be from various luxury brands.

Matturi Fine Jewelry totem jewel
Events & AwardsJul 10, 2024
IAC’s Gold and Diamond Conference to Focus on ‘Expanding Horizons’

The 14th annual conference will host panels on cross-sector collaboration, industry sanctions, and more.

Immediate Connections
Events & AwardsJul 10, 2024
Women’s Art Center of the Hamptons to Host Jewelry Exhibition

“Immediate Connections” will be on view from July 18-21.

Navneet Gems salt & pepper sapphires
SourcingJul 10, 2024
Navneet Gems Launches Salt-and-Pepper Sapphires

Sourced from Tanzania, the stones feature a unique hematite inclusion.

Buccellati butterfly brooch
TrendsJul 10, 2024
Amanda’s Style File: Slither and Fly

Snakes, birds, and bugs are all the buzz this summer.

Peter Smith
ColumnistsJul 09, 2024
11 and ½ Thoughts on Leadership

From prioritizing “big rocks” to practicing transparency, Peter Smith explores what it takes to be an effective leader.

John Hardy bracelet and Wölffer Estate Summer in a Bottle rosé
CollectionsJul 09, 2024
John Hardy Toasts to Wölffer Estate With New Collection

The capsule collection is inspired by the Hamptons vineyard’s Summer in a Bottle rosé.

Fuli Gemstones peridot The Curious Gem
SourcingJul 09, 2024
The Curious Gem Now Carrying Fuli Peridot

The U.K.-based online supplier will offer calibrated stones under 1 carat.

Graff’s fancy yellow and white diamond necklace
CollectionsJul 09, 2024
See Graff’s New High Jewelry Creations

The jewels are inspired by modern architecture with a focus on the play of light and movement.

×

This site uses cookies to give you the best online experience. By continuing to use & browse this site, we assume you agree to our Privacy Policy