Skip to Content

HPHT Diamonds: What Is HPHT Diamond? All You Need To Know

HPHT Diamonds: What Is HPHT Diamond? All You Need To Know

We’ve all heard of lab-grown diamonds as an alternative to natural diamonds. But, people often aren’t familiar with the process that needs to take place in order for lab-grown diamonds to form, grow – and be made in general.

Today, we’re going to talk about the HPHT process – the most popular, widely used process for producing lab-grown diamonds – and, more specifically, the HPHT diamonds that come out of it.

We’re purposefully not telling you (yet) what HPHT stands for here, but don’t worry; you’re going to find out soon enough. These diamonds are among the most popular in the world because of their wide availability and accessibility. Why is that? 

The HPHT process makes them multiple times cheaper than natural diamonds excavated from the depths of the Earth. Now, let’s look at what HPHT stands for, what is HPHT diamond, why they are so popular, and share some more interesting facts about these diamonds!

What Does HPHT Stand For?

Let’s start with the basics and tell you what HPHT stands for and explain what it actually means: 

HPHT is just an acronym. It stands for “high-pressure high temperature,” which carbon needs to form a diamond. High pressure and high temperature are conditions needed to form a diamond in nature – but it takes a lot of years for a decent-sized diamond to form. 

And, well, people don’t have time for that. Scientists have discovered a way to apply high pressure and high temperature (as in, extreme heat) and drastically shorten the time that elapses while the diamond forms.

This process may seem quite simple at first glance, but a lot of calculations about the amount of pressure and the high temperature go into this method in order for the diamond to come out as expected. 

The HPHT process takes place in controlled environments – in labs and under close surveillance of scientists. That’s why HPHT diamonds are more commonly referred to as lab-grown diamonds. Diamonds grown in a lab are actually the same on a molecular level as natural diamonds. The only notable difference is the controlled conditions and the time required for a diamond to form fully.

So, High-Pressure High Temperature (HPHT) is just a short name for the conditions and the process synthetic diamonds need to go through.

Is HPHT The Only Way To Make Synthetic Diamonds?

It’s common to call all diamonds grown in the lab “lab-grown diamonds,” and that’s because they are.

But, there have to be some distinctions between different methods of making diamonds in a lab, right? It’s true that it all comes down to extreme pressure and heat being applied to carbon – but’s it’s not that simple.

There’s also a process called CVD. CVD is a different way of producing man-made or synthetic diamonds, which also comes down to heat and pressure. However, it’s slightly different from the HPHT method of making lab-grown diamonds:

CVD – which stands for Chemical Vapor Deposition – is one of the commonly used processes that result in lab-grown or synthetic diamonds. The chemical vapor deposition begins with a diamond seed crystal, often coming from a high-quality synthetic diamond, that is then placed in a vacuum chamber.

A natural gas – for example, methane – is pumped into the chamber and then broken down into carbon atoms that then accumulate on the crystal, forming a diamond. Besides the natural gas, the crystal is treated with high temperatures and pressures within the chamber to remove any discoloration, making the diamond colorless.

That’s one of the most well-known alternatives to HPHT – and certainly one of the most popular techniques for making lab-grown diamonds worldwide.

Learn More: What Is The Difference Between HPHT And CVD?

Are HPHT Diamonds As Good As The Natural Diamonds?

Remember that natural diamonds form over a period of one to three billion years under extreme conditions of heat that require over 2,000 degrees Fahrenheit – and around 727,000 pounds per square inch of pressure. 

Making a lab-grown diamond doesn’t seem as simple as it once looked, huh?

HPHT is a method where all of these conditions are met artificially; here’s what that includes: HPHT diamonds are made in a process that requires a tiny diamond seed that’s then placed into a piece of carbon. The carbon containing the “diamond seed” is set in a press.

There are three types of these presses:

  • Cubic Press
  • Split Sphere Press (BARS)
  • Belt Press

All three of these presses do the same thing – applying pressure to the carbon that contains the tiny diamond seed in it.

The amount of pressure needs to exceed the amount of pressure that usually makes diamonds in the natural process. So, if we take into consideration that it takes around 727,000 pounds per square inch, these presses apply approximately 1.5 million pounds of pressure per square inch.

The heat level affects this tiny diamond seed inside the carbon. So, instead of the natural 2,000 degrees Fahrenheit, lab-grown diamonds withstand about 2,700 degrees Fahrenheit. You’ll notice here that the difference in the heat is somewhat smaller (around 33% more) than the difference in pressure (roughly twice as much). Why? 

It’s because the level of tolerance for heat in diamonds is lower than the tolerance for pressure. When these conditions are met, the lab-grown diamond starts to form around the small diamond seed placed in carbon and begins to turn the surrounding carbon into a diamond.

So, HPHT diamonds withstand even harsher conditions than real diamonds, which means they are as durable as natural stones. Both are graded as the hardest on the Mohs scale of hardness, which is impressive!

Also, these diamonds have higher clarity levels – and boast a more desirable color. Sometimes, natural diamonds are also put in HPHT presses to enhance their clarity or color grade. More on that later, though.

HPHT diamonds really look as good – if not better – as the natural diamonds found in the Earth’s layers. The only real difference is the time needed to form both diamonds. For lab-grown diamonds, six to ten weeks is all it takes – compared to up to three billion years needed to get a natural diamond.

Related Read: Lab-created Diamond Vs. Natural Diamond

Where Are HPHT Diamonds Used?

Given that they speed up the process of making diamonds, methods like HPHT became popular as soon as they were invented. On that note, they first started making lab-grown gems in 1956.

From that point on, HPHT diamonds only continued to gain popularity throughout the world. These diamonds reached the popularity of natural gems at one point – and the race for the ultimate diamond began.

People were pretty much instantly attracted to pieces of jewelry containing HPHT diamonds that were drastically cheaper than the pieces of jewelry containing natural diamonds. Of course, natural diamonds still have their fans worldwide – people who appreciate the “natural” aspect of these precious stones. And that’s perfectly understandable. It’s a matter of preference, really. 

But that hasn’t hindered the popularity of HPHT diamonds in the least bit. You’ll now find them in a wide range of jewelry pieces – and their “fan base” continues to grow by the day. 

Engagement rings, for example, are among the most sought-after pieces of jewelry that contain HPHT diamonds. Young adults started appreciating these synthetic diamonds more not only due to the more affordable prices but their eco-friendly nature, too.

Think about it: You can get an engagement ring that’s as beautiful – if not more beautiful – than one containing a natural diamond for a drastically lower price. How’s that not reason enough to consider these synthetic diamonds? 

Besides the jewelry business, other industries have also embraced the use of HPHT diamonds, too. First and foremost, we should mention that almost all diamond equipment is made from HPHT diamonds. Diamond drills, saws, and other types of heavy industrial machinery are made from these lab-grown diamonds. Lab-grown diamonds were seen as a fantastic way to bring down the cost of these expensive machines.

HPHT Synthetic Diamonds Pros & Cons

Now that we’ve gone over the essential information regarding HPHT diamonds, let’s look at their most notable strengths – and some of their weaknesses, as well. Only when you’ve seen those pros and cons side by side can you legitimately decide whether you like HPHT diamonds or not.

Pros Of HPHT Diamonds

The advantages of these synthetic diamonds are many, but we’ll keep it short and sweet for you. 

The number one thing would be that these diamonds are essentially identical to natural ones. An HPHT diamond has all the strengths that a natural one does. The Mohs scale of hardness is one of the first indicators of this claim: HPHT diamonds rank at the top of that list with a grade of 10 for hardness – the same as natural diamonds.

Also, these diamonds generally have exceptional clarity and higher color grade, better than any natural gem. Diamonds found in nature can be a bit “foggy” and not as clear as they should be – while HPHT diamonds are as close to perfection as possible.

The same goes for the color: Many things can influence the color of a diamond under natural circumstances, but when grown in a lab, the diamond is almost always completely transparent without any color to alter the light that passes through the HPHT diamond.

Finally, there’s the price: A synthetic diamond, like one made through the HPHT process, will always be cheaper than a natural one. 

Cons Of HPHT Diamonds

HPHT diamonds also have similar weaknesses and cons identical to natural diamonds. They’re extremely brittle and can be broken into pieces or chipped as easily as natural diamonds.

Also, if you like collecting diamonds or don’t look at them as gems to be worn but as something to invest in, you wouldn’t like a lab-grown stone in your collection.

Another thing to mention is the certificate. Natural diamonds will come with multiple certificates proving they aren’t blood diamonds, officially documenting their origin, and proving they are real diamonds. You don’t get the same with HPHT diamonds – although that’s hardly a downside. You’re still getting a diamond, after all. 

However, if natural diamonds interest you beyond jewelry, lab-grown diamonds probably won’t be that fascinating since they don’t have any “story behind them.”

Should You Buy HPHT Diamonds?

Now that you’ve seen the key strengths – and weaknesses – of these diamonds, let’s answer another crucial question: Are HPHT diamonds worth buying?

The first thing that we need to mention is that we are primarily talking about diamonds found in jewelry here. That’s the most popular use for all diamonds, after all – including HPHT diamonds and natural diamonds alike.

HPHT diamonds look, feel, and shine the same as natural diamonds. So, if you’re in the market for a pair of diamond earrings, a necklace, or maybe an engagement ring, there’s not a single reason not to go with HPHT diamonds.

Of course, if you’re a “purist” who prefers natural diamonds, then you have a subjective reason – and a valid one – not to go for the lab-grown HPHT diamond. 

But again, that is a matter of your personal preferences, nothing more.

HPHT diamonds cost around 50% less than mined diamonds. So, let’s say you’d like to buy a ring containing a 2-carat diamond: For a lab-grown diamond, you’ll pay around $10,000. It seems expensive – until you compare it to the cost of a natural 2-carat diamond that would set you back around $22,000.

Related Read: How Much Does It Cost To Make A Synthetic Diamond?


HPHT diamonds have been steadily gaining popularity since they were first invented in 1956. These diamonds made it possible for people who are less well off financially to afford diamond jewelry that looks and feels as good as the “real deal.” 

They are incredibly durable and typically have a much smaller price tag attached to them, which is always a plus. In addition to being popular in the jewelry world, HPHT diamonds are used for heavy industrial types of machinery, such as diamond drills, too.

HPHT diamonds are the better version of the natural diamonds in many different ways – unless, of course, you believe that the only diamonds that should be considered precious are the mined natural ones. But that’s up to you. Either way, we wish you successful diamond hunting!