How Diamonds Are Made

Really, you can interpret the question above in two ways. You can go with, ‘How does planet earth make diamonds?’ or, ‘How do people make diamonds?’ Since the principle is the same (even if the execution is different) I’ll explore both here. And we’ll start with the earth.

That seems only fair, don’t you think? After all, not only was she making them first, but if she hadn’t we wouldn’t even know about them! Even if we did – perhaps because we’d started making them in the lab – they wouldn’t hold the same significance. They wouldn’t grace wedding rings nor would we talk about them being a girl’s best friend.

How The Earth Makes Diamonds

How the earth makes diamonds

There is only a very small slice of our planet in which most diamonds form, which runs from about 140 to 190 kilometers (or 87 to 118 miles). That’s only about half a percent of the actual earth’s radius! Why is this the goldilocks zone of diamond formation? Because both the pressure and the heat are just right for carbon minerals to transform into diamonds.

Note that I said ‘carbon minerals’ and not ‘coal’. That’s because despite what you’ve been told, coal rarely becomes diamonds. It’s not that coal couldn’t become diamonds. It could. Instead, it’s more that there isn’t that much coal down at the right depth. Coal seams generally only go about 2 kilometers and there isn’t enough pressure or heat down there.

Even with the intense pressure of having 140 kilometers of rock sitting on top, it still takes a while for diamonds to form. How long? Somewhere between one to three billion years. That makes them about ten times older than dinosaurs!

And their formation is only half the battle. Because they still have to make their way up to us. If you thought we could dig down that low, you overestimate our technological prowess.  The deepest we’ve ever managed to dig is 12 kilometers (or 7 ½ miles). The Russians managed that at the Kola Superdeep borehole. That’s not even 10% of the way.

So how do diamonds make their way to the surface? Volcanoes. And not any ordinary volcano either. Those won’t do for this extraordinary rock. Their magma chambers only go about 50 kilometers down. The ones that go the necessary 150 kilometers are much rarer. That means only a small percentage of diamonds are brought up to the surface, which adds to their rarity.

How People Make Diamonds

How People Make Diamonds

Now, we can’t wait around a billion years for diamonds to form in the lab. I mean, I don’t know about you, but I’ve got dinner plans. Fortunately, scientists worked out ways that go a little bit faster than that. Modern diamonds can be made in as little as three weeks.

The two most used methods are known as ‘High Pressure High Temperature’ (HPHT) and ‘Chemical Vapor Deposition’ (CVD).

HPHT is how you’d imagine you’d build a diamond. In effect, you replicate what happens underground. You take a bunch of steel anvils, heat carbon to ridiculously high temperatures and then compress. Hey, presto! Diamonds.

The CVD method is a bit different. Here you don’t crush carbon together and force it into a diamond. Instead, you grow them. All you need is a special container, super-heated methane and hydrogen gas and some seed diamonds. The methane then converts to carbon, bounces around and occasionally strikes the seed diamonds.

Sometimes they’ll stick. If they align with the diamond’s underlying matrix, then they get lodged in place and become part of the diamond. If they don’t, then they’re not as firmly attached and the hydrogen will scour them off again. In this way, the diamond doesn’t end up with all sorts of impurities which would make it opaque, weak and brittle.

Did you know diamonds produced this way are purer than natural ones and will lack almost all faults of inclusions? In fact, that’s one of the ways you can often tell that a diamond is factory made!

So there you have it. That’s how diamonds are made by nature and humanity. It’s a fascinating process that takes some extreme conditions to give us these stones that we know and love. It also adds a nice bit of history to those rocks on our fingers or around our necks. Because that isn’t any stone. It’s one that has seen the inside of the earth, is older that multi-celled organisms, and has been part of a volcanic eruption. Now that’s impressive!

Diamond Appraisals – Jewelry & Diamond Ring Appraisal Process

We’ve talked a great deal here about the history and value of diamonds here. What we’ve not really spent any time on, however, is how a diamond’s value gets established in the first place. Do they pull a number out of a hat? Do they sacrifice a chicken?

You’ll be happy to know they don’t. Though they might as well read entrails for all the good that does you if you don’t understand what is going on. For that reason, today we’re going to address that oversight by giving you more insight. In that way, you’ll know what diamond appraisers are going to look at. That will allow you to judge whether what they are telling you is the truth or is so much hogwash.

That’s not the only thing we’re going to talk about, either. We’re also going to discuss which gemology groups are the more reputable ones. So that, even if you can’t judge with a high degree of accuracy the quality of the appraisal, at least you know if can trust the appraiser.

And that is almost as good!

The appraisal process

The appraisal process

A diamond is appraised on four different dimensions. These are:

  • Carat or the weight of the diamond.
  • Color where less color is more valuable.
  • Cut is how the diamond is proportioned.
  • Clarity the fewer faults (also called ‘inclusions’) the more valuable.



That’s not so hard, right? Let’s look at all these in more detail, so that you get a better sense what to look out for on those four dimensions.


Carats are the most straightforward of the four dimensions to measure. You can do so with any sensitive scale. One carat is 0.2 grams or a little more than 0.007 ounces. So if your stone weighs 1/10th of an ounce, you’ve got a 14 carat diamond.

Note that if your diamond is set in a setting, weighing it will obviously be a lot harder. In this case, the number of carats the diamond has can be measured by way of its dimensions. This is only an approximation, though.


The basic color rule is pretty straightforward. More expensive diamonds have less color. How is color measured? There are a few ways that this can be done, but the most popular way is to compare a stone to a master set.

Your stone is then awarded the color grading of the stone it most closely matches. Now, there are different color-grading scales, advanced by different gem institutes. In the US the one you’re the most likely to run into is the one created by the Gemological Institute of America or GIA.

Stone color runs from D to Z, where D, E and F are almost completely colorless and G to J stones are pretty damned close. You’ll generally only see a yellowish tint in stones rated from K to Z.


The better the cut the more valuable the diamond. This is because better cut diamonds look better. Not only that, they will trap and return the most light to the viewer’s eye, thereby giving the stone more sparkle.

There are many dimensions are considered when the cut of a diamond is evaluated. Here are a few of the more important ones:

  • The girdle: This is the thin slice at the broadest part of the diamond that separates the top of the stone (also known as the crown) from the bottom. It is what the setting will make contact with. This should be rated from ‘thin’ to ‘medium’. Too thin and it may chip.
  • Table percentage: This is calculated by dividing the diameter or width of the stone’s top most facet by the width or diameter of the girdle. The perfect relationship is 54 to 57%.
  • Depth percentage: This is calculated by taking the total depth (or height) of the stone and how this relates to the girdle’s width. Here the desired dimension is 61 to 62.5%
  • Crown Angle: This is the angle measured from the girdle towards the table top. The angle here should be at 34 to 35%.
  • Pavilion Angle: This is the angle in the other direction towards the point of the diamond. The desired angle here is 40.6 to 41%

Note that these dimensions are for round cut diamonds, which are the most likely ones you’ll find.



Then, finally, there is clarity. Clearer and more valuable diamonds have fewer faults, like carbon spots or lines.

The bigger the fault the more it affect value more. If you can see a fault with the naked eye, then will reduce the value of the stone a lot. On the other hand, if it can’t even be seen with a 10x magnification, then it’s not considered significant enough to affect clarity at all.

The setting

Note that a lot of these dimensions are a lot harder to assess when the diamond is in its setting. I already mentioned that it’s much harder to weigh a stone that way. That’s not the only thing that is affected, though.

For example, the color can be a lot harder to assess. This is particularly true if the setting isn’t white. Similarly, inclusions or faults can be difficult to spot when the stone is not taken out.

For that reason, don’t be surprised if the appraiser asks to take the stone out of the setting to evaluate it. That’s perfectly normal. At the same time, if you don’t trust the appraiser, then don’t leave them alone with the stone, so they can’t switch it while you’re away.

Diamonds in setting

Which labs can you trust?

Finally, let’s discuss the different labs that are out there. The four best known are:

  • The Gemological Institute of America (GIA)
  • The American Gem Society (AGS)
  • The European Gemological Laboratory (EGL)
  • The International Gemological Institutes (IGI)

Which labs can you trust?

Generally, you’d be better of getting your diamonds rated by the first two, as these are considered more reputable.

Having a certification is not only good for you, but good for our listed diamond buyers as well. They can make an estimate for your diamond from the appraisal information provided by these organizations quickly and easily (final offers are typically made after examination to confirm).

Many industry insiders strongly advise you to avoid IGI certified diamonds. This is because they frequently overrate their diamonds. That means you’re going to pay an inflated price.

It won’t help you if you get the stone you’re holding assessed by them either. For in many markets you’ll often be offered a lower price for the same grade when they’ve rated it. This is because diamond experts are aware of IGI’s tendency to overrate and figure this into the prices they are willing to pay.

So yes, the IGI might be cheaper to use than the others, but this comes with a price!

Last words

So there you have it! A crash course in what to look out for in your diamond as well as what companies you should use. Armed with this knowledge you’ll be better prepared. For you’ll have a better idea of what your stone is worth, what to look for in the diamonds you’re buying and how to get it certified as accurately as possible.

And that will mean that when you buy and sell diamonds you’re in a much better position to get the best deal you can get. Now isn’t that a nice bit of peace of mind?

Customer Reviews on the Best Diamond Buyers

diamond-buyer-reviewsAt Top 5 Cash for Diamonds we have tried the services of the diamond buyers that we have reviewed a number of times in order to help you gather a perspective on what to expect when selling your jewelry and diamonds online. While our reviews can provide you with great insight on what to expect from each diamond buyer, seeing what past customers who were once in a similar position as yourself had to say, can benefit you even further. Below is a short review on each of the top 3 diamond buyers from a customer who recently used their service. You can see what they had to say, and then choose the diamond buyer that is best for you.



Diamond Buyers International Review by Ashley G.

I was in need of money and had taken an old pair of diamond earrings to the pawnshop and was less than pleased with their offer. I was suggested to try selling them online and came across Diamond Buyers International. I figured I had nothing to lose and sent in my earrings. I received an email and phone call just two days later with an offer that was almost twice as much as the pawnshop. I was really pleased with the money that I received and plan on selling more jewelry to them in the future.

Diamond Buyers Intl. Review

WP Diamonds Review by Marissa

I still had my engagement ring from a previous marriage and thought it was time to sell it. WP Diamonds was recommended by a friend and I would highly recommend them to others. I have to admit, I was hesitant about sending the ring off in the mail, but their customer service was excellent and made me feel confident that everything was going to be fine. I had never sold my jewelry online before, and the experience was very nice and would do it again.

WP Diamonds Review

Cash for Diamonds USA Review by Alex W.

Selling scrap gold and old jewelry to local pawnshops was always the way I cashed in on the things I collected, until I had a diamond ring. They claimed they could not tell if it was real or what it might be worth because they cant grade diamonds. After looking at diamond buyer online I decided to try Cash for Diamonds. They purchased the ring and I received my money in my bank account very shortly after. If you have diamonds, then you are likely better off selling them online.

Cash for Diamonds USA Review

These are some of the things that past customers had to say about our top ranked diamond buyers. Experiences will vary from person to person, but generally these businesses have all been operating with a positive reputation for many years now. Each buyer may offer something different, such as insurance value, turnaround time, or even payout, so having these reviews can help you find the unique differences in an otherwise standardized process. Browse around our site to see the other info we have to offer that could help you earn more money for your diamond jewelry.

GuaranteeYear In
Instant QuoteShipping Method
#1Diamond Buyers Intl.$5,000A+30 Days11 YearsYesFedEx
#2WP DiamondsActual ValueA+None4 YearsNoFedEx

Top 6 Most Popular Diamond Colors

Diamonds are more than a girl’s best friend. They are beautiful gems that come in different shapes, sizes, and colors. That’s right, colors. Diamonds are highly versatile and can match any person’s individual style. Most people are attracted to color diamonds for their beautiful hues and their rarity. They can be quite expensive, however. Usually, the rarer the diamond the more expensive it is, but that does not deter people from admiring or purchasing them. Here are the top 6 most popular diamond colors.

1.   Colorless Diamond

Colorless Diamonds are the most popular and classic among the colors. It is the purest form of the diamond, and it has been worn by celebrities and royalty, adorning engagement rings, crowns, and other pieces of jewelry.

Colorless diamonds

2.   Cognac Diamonds

Cognac Diamonds are popular for the rich brown and golden color and their resemblance to the luxury drink, hence the name. These diamonds can be found in the Argyle mine in Western Australia.

cognac diamonds

3.   Champagne Diamonds

Champagne Diamonds are a deeper brownish color and belong to the same color spectrum of diamonds as Cognac Diamonds. They can be found in the same mines as the Cognac Diamond, such as the Argyle mine. The most famous piece among Champagne Diamonds is the Golden Pelican. The Golden Pelican is a rectangular emerald-cut diamond placed in a 14kt Gold band and was once owned by Baron Corso de Palenzuela con Habsburg and was later auctioned off in the 1970s.


4.   Koi

The Koi Diamond has over 32 carats and is certified by the Gemological Institute of America (GIA). It has a variety of colors including white, orange, yellow, dark blue, and black. The diamond is famous in Eastern Asia, especially China, for their color and resemblance of the koi fish, which has great significance and legend in that area.

koi diamonds

5.   Blue Diamonds

Blue Diamonds are highly popular because of the many hues and intensities that it has. From light blue to greenish blue colors, you will also find this diamond in many shapes and cuts. These diamonds can be found in mines located in Africa, India, and Australia. One of the most famous blue diamonds is the Hope Diamond. The Hope Diamond, which is currently on exhibit at the National Museum of Natural History in Washington, was owned by numerous people including King Louis XIV. It has been rumored to bring misfortune to its owners and wearers.

blue diamonds

6.   Gray

Gray Diamonds are mostly popular for their rarity and their price range being on the lower end despite their rarity. Many people have favored gray diamonds for their engagement rings because of their rarity and price. They are often found in circular, oval, cushion cut, and pear shape. The color of the gray diamond can be described as a colorless diamond with a metallic tint. You can find other color combinations of gray diamonds such as gray yellow or gray violet.

grey diamonds

They are many more popular colors and hues of diamonds, and unfortunately we couldn’t include all of them. It is a shame since the beauty and uniqueness of these color diamonds are a sight to behold and highly special to own.