HPHT vs. CVD Diamonds: What’s the Difference?

Nov 11th 2022

HPHT vs. CVD Diamonds: What’s the Difference?

You’re practically dancing because you just found TWO perfect engagement rings for the love of your life. But…which should you choose? One features an HPHT diamond and the other features a CVD diamond. What does that even mean? Is one better than the other? We’re here to break it all down, so you can start planning your happily ever after.

What is a Lab Grown Diamond?

First, let’s start with some basics. HPHT and CVD diamonds are both considered lab grown diamonds, which means they’re created in laboratories. But even though they’re man-made, they’re still real diamonds! They’re made of carbon and have the same qualities as natural diamonds, including look, durability and sparkle. In fact, only trained gemologists can tell them apart using special equipment.

High Pressure, High Temperature (HPHT) Diamonds

HPHT stands for “high pressure, high temperature,” and it’s the primary process for growing diamonds in a laboratory. Basically, conditions that formed natural diamonds below the Earth’s surface are recreated with high pressure and high temperatures. As a result, lab grown diamond crystals develop.

We’ll show you how it actually works:

● First, a tiny diamond seed is inserted into a piece of carbon. The carbon molecule is then placed inside of a chamber that was specifically designed for the diamond growth process.

● Now, a great amount of pressure – about 1.5 million pounds per square inch – is applied to the growth chamber. It’s also heated to more than 2,700 degrees Fahrenheit!

● These extreme conditions cause the carbon molecule to split into little pieces and fall onto the tiny diamond seed. As a result, a diamond starts growing around the seed!

● This new diamond is cooled, polished by a diamond cutter and eventually placed into the beautiful engagement ring settings that you see in your local jewelry store.

Chemical Vapor Deposition (CVD) Diamonds

Chemical Vapor Deposition (CVD) is another common process for creating lab grown diamonds. Molecules of a carbon-rich gas, like methane, are broken down into carbon and hydrogen atoms. These atoms are later used to develop a square-shaped diamond crystal. This procedure involves lower temperature and upfront equipment costs than the previous process, but most CVD-grown diamonds need further treatment to enhance or change the stones’ colors.

Let’s dig into this technique:

● A tiny diamond seed is sealed inside of a vacuum chamber.

● The chamber is then exposed to temperatures greater than 1,400 degrees Fahrenheit and usually filled with methane and hydrogen.

● A microwave beam deconstructs the gases, releasing carbon. These carbon pieces stick to the diamond seed and ultimately start creating a new diamond crystal.

● Every few days, the developing diamonds are taken out of the chamber and polished to remove excess carbon. They’re returned to the chamber to complete the growth process.

● When the stones are ready, they’re cut, perfected and fashioned into engagement rings and other jewelry.

Why Choose a Lab Grown Diamond?

Although gem-quality, lab grown diamonds have been available since the early 1970s, they’re now a growing trend. Why? It’s partly due to diamond demand. Natural diamonds formed billions of years ago below the Earth’s surface, making them precious and one-of-a-kind. In addition to that, only about 30% of mined natural diamonds qualify to become gems.

Since there’s no limit on the supply of lab grown diamonds, gem-quality stones are often more affordable and produced more quickly. In fact, lab grown diamonds in most sizes are typically produced in less than a month. Plus, some in the jewelry industry argue that lab grown gemstones have an edge over natural diamonds when it comes to eco-friendly options.

Have a question? We can help!

Gage Diamonds is Chicago's premier jewelry showroom and online retailer of engagement rings, wedding bands, and fine jewelry. We offer a selection of dazzling lab grown diamonds, including HPHT and CVD gems, as well as handpicked, certified natural diamonds.

We’re committed to helping you find the ring of your dreams. Browse our selection of lab grown diamonds and natural diamonds or set up an appointment with a member of our trusted staff at our in-person showroom.

We offer no-credit-needed financing – feel free to apply and get your approval within 24 hours!

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