CVD vs HPHT Lab Grown Diamonds: What’s the Difference?

May 19, 2025 Lydia Sanderson Off General,

In the world of lab grown diamonds, two advanced technologies dominate the industry: Chemical Vapor Deposition (CVD) and High Pressure High Temperature (HPHT). Both methods produce genuine man made diamonds that are chemically and physically identical to mined diamonds—but the processes behind them are very different. If you’re considering buying a lab-grown diamond, understanding the difference between cvd vs hpht can help you make an informed and confident choice.

Table of Contents

What Are Lab Grown Diamonds?

Lab grown diamonds are real diamonds created in a laboratory setting rather than being mined from the earth. They have the same physical, chemical, and optical properties as natural man made diamonds but are more sustainable, affordable, and ethically produced.

There are two primary methods for creating lab-grown diamonds:

CVD (Chemical Vapor Deposition)
HPHT (High Pressure High Temperature)

What Is HPHT?

The HPHT method replicates the natural conditions deep beneath the Earth’s surface where diamonds form—extreme pressure and high temperatures.

How HPHT Works:

A small diamond seed is placed in a chamber.
The chamber is heated to over 1,500°C and pressurized to about 1.5 million pounds per square inch.
Carbon is introduced and starts to crystallize around the diamond seed.
Over several weeks, a full-sized diamond is grown.

Pros of HPHT:

Produces diamonds with excellent clarity and hardness.
Good for creating colorless or near-colorless diamonds.
Ideal for enhancing the color of lower-grade diamonds.

Cons of HPHT:

May sometimes leave metallic inclusions that can be detected.
Energy-intensive process.
Diamonds may fluoresce under UV light, depending on growth quality.

What Is CVD?

The cvd vs hpht process uses a vacuum chamber and hydrocarbon gases to grow man made diamonds layer by layer.

How CVD Works:

A diamond seed is placed in a low-pressure chamber.
A carbon-rich gas (like methane) is introduced.
Microwaves heat the gas to form plasma, breaking down the molecules.
Carbon atoms settle on the seed, building the diamond layer by layer.

Pros of CVD:

More energy-efficient and cost-effective than HPHT.
Often results in fewer metallic inclusions.
Easier to control purity and grow high-quality diamonds.
Often more consistent in structure and color.

Cons of CVD:

Sometimes displays brown or gray tints (which can be treated).
Requires post-growth treatments like annealing to improve color.
May include internal strain or graining visible under magnification.

Visual Differences

To the naked eye, both HPHT and cvd vs hpht man made diamonds look the same as mined diamonds. However, under high magnification and advanced testing, lab technicians can identify growth patterns unique to each method.

HPHT diamonds often display a cubic growth pattern.
CVD diamonds may show a layered or “striation” pattern.

Retail buyers, however, will not notice any difference without advanced tools.

Pricing Differences

In general, cvd vs hpht man made diamonds tend to be slightly more affordable due to the lower cost of production. HPHT diamonds, especially colorless ones, can command higher prices because of their clarity and color quality.

Final Thoughts

Whether you’re looking for an lab grown diamonds earrings, or a pendant, both cvd vs man made diamonds offer a brilliant, ethical, and budget-friendly alternative to mined stones. Understanding the differences between the two can help you choose the right diamond that fits your values, style, and budget.

When buying, always ask your jeweler which growth method was used and request certification from reputable labs like IGI or GIA. That way, you can ensure you’re getting exactly what you pay for—beautiful, conflict-free sparkle that lasts a lifetime.