Everything You Ever Wanted to Know About Diamonds

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Podcast Transcript

It has been said that they are a girl’s best friend, they are forever, and that they are the hardest substance in the world. 

In nature, they are created deep beneath the Earth at extreme temperatures and pressures, yet in the laboratory, they can be created in a near vacuum.

For all practical purposes, you can’t scratch it, yet you can cut it, and economists have noted the paradox of how it is priced compared to water. 

Learn more about diamonds, how they are made, and how they are used, on this episode of Everything Everywhere Daily.

Before I go into the history of diamonds, I should start with the physics and chemistry of diamonds. 

As you probably know, diamonds are made out of carbon. That’s it. Just carbon. 

With four electrons in its valence shell, there are a lot of ways that carbon can bond with other atoms. It is why the chemistry of carbon, aka organic chemistry, has so many different carbon-based molecules.

When carbon binds to itself, however, there are only a few ways it can do it. Those ways, however, can result in materials with remarkable properties. 

The most common form of carbon is graphite. This is a two-dimensional allotrope of carbon where the carbon atoms are aligned in a single sheet. A single sheet of these is known as graphene, and when the sheets are found in stacks it is known as graphite. 

Many of the other allotropes of carbon are just different forms of graphene where the sheet is turned onto itself to form cylinders or spheres. 

Under much higher temperatures and pressures, carbon atoms can align in other ways. In particular, for the purposes of this episode, carbon atoms can align in a 3D crystal lattice to form diamonds. 

The naturally occurring diamonds found on Earth were all probably created over a billion years ago at depths of 150 kilometers or 90 miles below the surface.

Pressures at that depth would be anywhere from 237,000 to 1.3 million atmospheres of pressure and the temperatures would be between 1000 to 3700° Celsius.

Diamonds that managed to come to the surface do so via deep volcanoes. There are only a few places on Earth that have these deposits. By far the largest is in South Africa, with other significant deposits in Canada, Russia, and Australia. There are a host of smaller diamond mines in other countries around the world. 

Diamonds do have a melting and boiling point and they can burn. If you heat up a diamond with a torch and drop it into liquid oxygen, it will completely turn to carbon dioxide. Melting a diamond is hard because it tends to convert to graphite before it turns to a liquid. 

Diamond also had the best thermal conductivity of any known substance, meaning it would make the worst thermal insulator. 

As you are probably aware, diamonds are the hardest naturally occurring substance. Nothing can scratch a diamond. The hardness of a diamond is due to the bonds between the carbon atoms. On both the Vickers scale and the Moh’s hardness scale, diamonds are the hardest substance. 

However, diamonds are not the hardest theoretical substance, nor is it even the hardest theoretical carbon allotrope.  There is a version of carbon called Lonsdaleite, which is a type of diamond that has a hexagonal lattice instead of a cubical lattice in a regular diamond. 

Lonsdaleite is very rare and has only been found in very small amounts in meteorites, and it has been created in laboratories. In a pure form, it is 58% harder than diamond, but in reality, cracks and impurities usually make it less hard. 

There are four traditional ways that gemologists evaluate the quality of a diamond. They are known as the four C’s: Color, Cut, Clarity, and carat weight. The Gemological Institute of America has scales and methods for grading each of these measures. 

The color of a diamond comes from impurities of non-carbon atoms that are embedded into the crystal lattice. Pure diamonds are clear-colored. However, there are colored diamonds as well. Blue, yellow, pink, green, purple, and black. 

Yellow diamonds are actually the most common, and the yellow coloration comes from nitrogen. The famous Hope Diamond is a blue diamond, and the blue comes from small amounts of boron found in the crystal.  Green diamonds come from exposure to alpha radiation. 

You can see the Hope Diamond on display in the Smithsonian Museum of Natural History in Washington DC.

The clarity of a diamond is something that is determined via a microscope. Clarity refers to blemishes and inclusions in the diamond. These are not impurities that cause changes in color so much as just breaks in the crystal lattice. 

Clarity measurements are on a 10-point scale from flawless to Inclusion 2, which means there are a lot of flaws. 

The cut of a diamond is probably the most important criterion for determining price. The cut of a diamond determines how light will move through the diamond and will determine its brilliance and how much its sparkles. 

A diamond is cut by an expert diamond cutter. They take an uncut natural diamond and have to make a unique plan to cut it based on the shape of the uncut diamond. 

Most of the world’s diamond cutting only occurs in a few places. The overwhelming majority of diamonds in the world are cut in Surat, India, located in the state of Gujarat. Antwerp is one of the other major centers for diamond cutting.

The final measure of a diamond is its carat weight. Carat is a measure of the size of a diamond. One carat is equal to 200 milligrams, and a carat can be measured in increments of 1/100ths, or 2 milligrams. 

A 5-carat diamond, which is quite large and would be very noticeable if you were to wear it as a ring, weighs only 1 gram.

Historically, the weight of a carat differed in different locations, but a global metric carat standard was set in 1907.

While diamond themselves are interesting, it probably isn’t as interesting as the diamond business, of which there really isn’t else in the world quite like it. 

The global diamond trade is highly centralized with only a few major players around the world. The largest company, by a wide wide margin, is De Beers.

De Beers is active in almost every aspect of the diamond industry from mining to trading to marketing. At one point they controlled 85% of the world’s diamond trade.

De Beers was founded in 1888 in South Africa by Cecil Rhodes. One of the first diamond mines was found in Kimberly, South Africa. Today it is known as the Big Hole. 

The Big Hole is, as the name would suggest, a great big hole, an open-pit diamond mine. I actually visited it several years ago and it is really staggering how big it is. They have a viewing platform that extends out over it.

What is really amazing about it is that it was dug by hand. From 1871 to 1914, 50,000 men with picks and shovels dug the hole in search of diamonds. A hole that is 463 metres or 1,519 feet wide, and 240 metres or 790 feet deep.

This early diamond mine in Kimberly gave name to the igneous rock which can contain diamonds: Kimberlite. These Kimberlite pipes are what miners look for when searching for diamonds. 

While most diamond mines are run as proper mines in the ground with machinery, in some parts of the world diamonds can be found in a method similar to panning for gold. This is the way they are usually discovered in less developed African countries like Sierra Leone, Ivory Coast, Liberia,  Angola, and the Democratic Republic of Congo.

Because these diamonds can be acquired so easily with nothing but human labor, they have often been used to fund insurgencies and civil wars by warlords who control diamond-producing areas. These are known as blood diamonds or conflict diamonds. 

An international program known as the Kimberly Process was implemented to track diamonds internationally and to certify diamonds as having not come from conflict zones. 

While most people are familiar with diamonds as gemstones, and that is the reason why they are mined because of their high value, by weight, the vast majority of diamonds are not used in jewelry. About 80% of all diamonds are used for industrial purposes. 

The 4 C’s of color, cut, clarity, and carat weight don’t really matter for industrial diamonds. These are diamonds that are too small, too low quality, and are the residue of the gem cutting process. 

Industrial diamonds are used for abrasives and cutting tools. You can actually buy poor-quality, industrial diamonds on eBay for a surprisingly cheap price. 

Diamonds are also used when doing extreme high-pressure experiments. When scientists conduct experiments with extreme pressures, they are usually using what is called a diamond anvil. A diamond anvil is just two diamonds where the tips are compressed in an extremely small area, well under a millimeter, to create enormous pressures.

The biggest change to the diamond industry in the last several decades has been the introduction of synthetic diamonds. As diamonds are nothing by carbon, the recipe for them is simple. 

There are two techniques used for creating artificial diamonds: the first is high temperature, high pressure, and the second is called chemical vapor deposition. 

The first documented creation of an artificial diamond occurred in 1953 in Sweden. This was done via the high pressure and temperature method, and the resulting diamonds were of poor quality. 

The first gem-quality stones were created in 1970 by General Electric. These stones were all initially yellowish, but have gradually improved over time. 

The chemical vapor deposition technique allows for a charged gas to settle and create diamonds over a large surface area. This could allow for materials such as diamond-coated glass in the future. 

Synthetic diamonds have been gaining in popularity which has of course freaked out the traditional diamond miners such as De Beers. Chemically, they are exactly the same, however, you can usually tell the difference if you look at it in a spectrograph with ultraviolet or infrared light.  

Synthetic diamonds usually sell for much less than traditional diamonds, and most people can’t tell the difference unless you are an expert with special equipment. 

De Beers has both created marketing campaigns against synthetic diamonds and have also joined the party by creating their own. 

The potential for synthetic diamonds is enormous, including their potential as semiconductors.  

The subject of De Beers’ marketing campaigns brings me to the thing that diamonds are best known for: engagement and wedding rings. 

A wedding or engagement ring is the only time someone might actually purchase or wear a diamond. The reason we do this is that it is a tradition that dates back thousands of years. 

….except it isn’t.

The tradition of diamond engagement rings is a completely modern invention invented by De Beers and their New York advertising agency N.W. Ayers in 1938. 

Yes, there were diamond rings given by European royalty as early as 500 years ago, but there were all sorts of precious gemstone rings that were made. There wasn’t anything particularly special about diamonds. 

De Beers, having controlled the world’s diamond market, needed to create demand for their product. They began selling the idea that only diamond rings were true symbols of love. They would promote the enormous diamonds worn by Hollywood stars. 

From 1939 to 1979, the US diamond market grew 100-fold. 

They replicated this strategy all over the world. In Japan, 5% of women in had a diamond engagement ring in 1967. By 1981, it had risen to 60%. Almost 30% of Chinese brides have diamond rings today, up from basically zero in 1990. 

The adoption of diamond wedding and engagement rings, and the idea for men to spend three months’ salary on one, is totally an invention of the diamond industry and advertising companies. 

In 2019, the global diamond industry reached $90 billion dollars. 

I want to end on something that economists call the diamond and water paradox. 

Outside of a few industrial uses, diamonds basically have no real use. They are pretty stones you can look at, and that’s it, Yet, they are very expensive. 

Water is something that all of us would die without if we didn’t have it for even a few days. Yet, despiting being vital for life, it is relatively cheap. 

Why is something useless so expensive, and why is something so vital so inexpensive?

The answer to the puzzle led to one of the great revolutions in economics. The idea of marginal utility, of which there will be a future episode.

A consumer doesn’t have to choose between all the diamonds and all the water. If we had to make that decision, we’d all choose water. Instead, we choose between the next glass of water or the next diamond and given the enormous supply of water, and the very limited supply of diamonds, diamonds end up costing much more. 

Diamonds are fascinating chemical substances, which are created by an extreme geological process, and traded by one of the few truly global cartels.

Given all of the incredible forces at play, both geologic and economic, diamonds probably will be forever. 


The executive producer is Darcy Adams.

The associate producers are Thor Thomsen and Peter Bennett.

I want to give a shoutout to the three people who figured out the hidden message at the end of the morse code episode.

Dreb Scott, Sevy, and Yo55i all figured out the puzzle and came up with the correct answer. 

I’m not going to give away what it was as I’m guessing some of you didn’t even know there was a secret message at the end of the show. If you want to take a stab at it, you can relisten to the morse code episode to try to solve it. 

I also have to give a big shoutout to Dreb Scott who sent me a 60,000 satoshi boost for the Morse Code episode. In his boostagram he wrote:

I likely would not have got my ham radio license if they still required Morse Code. That being said, I now want to learn it. Great episode!

Dreb, I think that was the case for a whole lot of ham radio operators. I only got my license for VHF and UHF because of the morse code requirement. That being said, I think it is something that if you practice a little bit everyday, you could probably figure it out. It really is just the alphabet in another form. 

KC0PE signing off, reminding you that if you leave a review or send me a boostagram, you too can have it read the show.