Diamonds dazzle with their captivating brilliance, fire, and unmatched hardness. For centuries, people have prized these precious gems both for their mesmerizing beauty and rarity. So much, in fact, that people have looked for ways to make diamonds out of countless types of materials using numerous creative methods. But it wasn’t until the 1950s that the first HPHT diamond was successfully created.

If you’ve ever wondered about the high pressure high temperature (HPHT) method for creating diamonds, we have all the info you need here.

What is High Pressure High Temperature (HPHT)?

HPHT stands for “high pressure, high temperature” and is the name of the process used to grow lab diamonds. It’s also a process used to color treat both natural and CVD diamonds.

CVD and HPHT Diamonds

The HPHT process is one of two methods used today to grow lab diamonds, the other method being chemical vapor deposition (CVD). Even though the outcome of both methods is lab grown diamonds, the CVD process is quite different from HPHT and it is newer.

If you’d like to learn more about HPHT vs CVD be sure to check out this article that compares the two.

How an HPHT Diamond Grows

HPHT lab diamonds start as diamond seed crystals. Then, under tremendous heat (1300-1600 °C) and pressure (above 870,000 pounds per square inch), a diamond begins to form from those seed crystals. This process is similar to the type of environment in which a natural diamond forms while buried deep within the earth.

When a diamond forms in the earth it can take billions of years to complete. However, when a diamond is grown in a lab it can take anywhere from weeks to months to complete the growth process.

The Origins of HPHT lab grown diamonds

HPHT diamonds were first created in the 1950s by H. Tracy Hall of General Electric. Hall produced these diamonds using a fairly simple belt press he created. This was a world-changing innovation; however, early HPHT presses could only produce small, low-quality diamonds that were best used for industrial purposes.

These industrial-quality diamonds were mostly used for tools that did cutting and grinding. But just a few decades later, companies were growing gem quality diamonds over 2 carats using the HPHT method.

On its own, the HPHT method of creating lab diamonds was an incredible scientific breakthrough, but there are other benefits to it as well. One of these exciting benefits is its color-ehancing capabilities.

The Color-Enhacing Quality of HPHT Treatment

The extreme heat and pressure of HPHT treatment transforms brown and yellow-hued natural and CVD lab diamonds into diamonds that could, in some instances, pass as colorless. And in addition to enhancing and improving the overall color of diamonds, HPHT treatment can also turn them pink, blue, green, or even yellow.

HPHT can achieve this color enhancing effect because it is a form of annealing.

According to the Gemelogical Institute of America (GIA), “Annealing is a controlled heating and cooling process that is often used after irradiation to further adjust a diamond’s color.”

HPHT Diamonds vs. Natural Diamonds

While both types of diamonds are beautiful, HPHT diamonds and natural diamonds differ in origin and in the benefits they offer–benefits that go beyond aesthetics and include cost effectiveness, environmental kindness, and ethicalness.

As you know by now, HPHT diamonds grow in labs under precise conditions that mimic the way natural diamonds form in the earth. Whereas natural diamonds are the result of billions of years of growth and development deep below the earth’s surface.

Lab grown diamonds don’t cause the same damage to the environment that natural diamonds do because they don’t have to be mined. They are also a more ethical option because people are not put in danger to mine them or forced into mining them against their will.

HPHT Diamonds are Less Expensive Than Natural Diamonds

In general, lab grown diamonds (whether HPHT diamonds or CVD lab grown diamonds) are much less expensive than mined diamonds. In fact, lab diamonds are anywhere from 30-50% less expensive than naturally occurring diamonds. This is simply because there are less logistics involved in producing a lab diamond.

Misconceptions About HPHT Diamonds

There are many misconceptions about HPHT diamonds. Some people consider a lab grown diamond produced with the HPHT method to be “fake.” However, HPHT diamonds are optically, physically, and chemically identical to natural diamonds–they’re just produced differently.

They’re not fake, although sometimes they are referred to as “synthetic diamonds.” And you shouldn’t confuse HPHT lab grown diamonds with cubic zirconia (which many people do). Cubic zirconia isn’t even a synthetic diamond, it’s a diamond simulant. A diamond simulant looks like a natural diamond but is often made from other materials like glass.

Other people view HPHT treatment, which is sometimes done to enhance the color of a CVD diamond, as deception. But all diamond jewelry undergoes some degree of cutting and polishing to maximize appeal. Even polki diamonds, diamonds in their raw and most natural state, often undergo some type of treatment. HPHT just accelerates this enhancement process.

Should You Choose an HPHT Diamond Over a Natural Diamond?

Only you can decide which is best for you. Because at the end of the day, whether you choose an HPHT diamond or a natural diamond depends on your priorities.

Do you want more sparkle for your money? Then HPHT (or lab grown diamonds in general) are the way to go.

Does the negative environmental impact of diamond mining weigh heavy on your conscience? Do you also worry about the unethical treatment of people who mine diamonds in other countries?

When you choose lab grown diamonds you don’t have to worry about either of these highly important issues. You can be 100% sure your purchase is 100% ethical when you purchase lab grown diamond jewelry.

How To Care For and Clean HPHT Diamonds

HPHT diamonds require the same type of care that any natural diamond requires.

Be sure to remove your diamond jewelry before working out, cooking, swimming, or doing anything active–especially if it’s a ring or bracelet. Rings and bracelets are more susceptible to damage and everyday wear especially if you work with your hands.

To clean an HPHT diamond, gently scrub it with a soft brush and mild dish soap mixed with warm water. Avoid using harsh jewelry cleaners as they can affect your jewelry’s metal. You should also avoid ultrasonic and steam cleaners because they can damage your diamond, loosen prongs, and make inclusions worse.

We recommend having a jeweler inspect and clean your diamond jewelry every 6 months if possible.

The Future of HPHT Diamonds

Lab grown diamonds created with the HPHT method are sure to continue growing in popularity over the coming years. Not only are they beautiful, they’re also well-priced and both ethical and conflict-free. These qualites will continue to be attractive to the modern consumer who prefers sustainable luxury items.

Lab Grown Diamonds From Clean Origin

If you’re looking for the perfect diamond jewlery, look no further than our selection of exquisite and affordable lab grown diamonds. We offer a variety of jewelry pieces, from unique diamond engagement rings to channel set engagement rings. We also have diamond station necklaces, bridal jewelry, diamond hoop earrings, and much more.

If you’d like help choosing the perfect diamond our experts are on hand to help you through every step of the process. Feel free to make an appointment for a virtual consultation here, or visit one of our gorgeous showrooms in person. Our friendly and knowledgeable staff are waiting to help you with anything you need.