How Are Lab Grown Diamonds Made? CVD & HPHT Explained

If you've ever wondered how a diamond can be grown in a lab, you're not alone. It sounds like science fiction, but it's been happening for decades. Today's lab grown diamonds are chemically, physically, and optically identical to mined diamonds. The difference is how they're created.

This guide explains the two main methods used to grow diamonds in a lab: CVD and HPHT. By the end, you'll understand exactly how a lab grown diamond is made.

The Short Answer

Lab grown diamonds are made by replicating the natural conditions under which diamonds form underground. There are two main methods:

• CVD (Chemical Vapor Deposition) — Carbon atoms are deposited onto a diamond seed inside a vacuum chamber, growing the diamond layer by layer.

• HPHT (High Pressure, High Temperature) — Carbon is subjected to extreme heat and pressure, mimicking the conditions deep within the earth.

Both methods produce real diamonds. The result is a diamond with the same chemical composition, crystal structure, and optical properties as a mined diamond.

Method 1: CVD (Chemical Vapor Deposition)

CVD is one of the most common methods for growing diamonds in a lab. Here's how it works:

1. A diamond seed is placed in a vacuum chamber. The seed is a small slice of diamond that serves as the foundation for the new diamond.

2. Carbon-rich gas is introduced. The gas contains carbon atoms, which are the building blocks of diamond.

3. The gas is heated to extreme temperatures. This causes the carbon atoms to break apart and bond to the diamond seed.

4. The diamond grows layer by layer. Over several weeks, the carbon atoms accumulate on the seed, growing a new diamond.

The result is a diamond that is chemically identical to a mined diamond. CVD diamonds are often used in jewelry because they can be grown to precise specifications.

Method 2: HPHT (High Pressure, High Temperature)

HPHT is the other main method for growing diamonds. It mimics the conditions deep within the earth's mantle, where natural diamonds form.

Here's how it works:

1. Carbon is placed in a growth cell. The carbon source is usually graphite or another carbon-rich material.

2. Extreme heat and pressure are applied. The growth cell is subjected to temperatures above 1,400°C and pressures of about 5-6 GPa.

3. The carbon melts and forms a diamond crystal. A small diamond seed helps the carbon crystallize into a diamond structure.

4. The diamond grows over several days to weeks. The result is a rough diamond that can be cut and polished.

HPHT diamonds are indistinguishable from mined diamonds in terms of composition, hardness, and brilliance.

CVD vs HPHT: What's the Difference?

Both methods produce real diamonds. The main differences are in how they grow and the equipment used.

In practice, both methods produce diamonds that are chemically, physically, and optically identical to mined diamonds. The choice of method depends on the manufacturer and the type of diamond being grown.

Are Lab Grown Diamonds Real?

Yes. Lab grown diamonds are 100% real diamonds. They have the same chemical composition as mined diamonds: pure carbon. They rank 10/10 on the Mohs hardness scale. They have the same brilliance and fire.

The Federal Trade Commission (FTC) officially classifies lab-created diamonds as real diamonds. That means when you buy a lab grown diamond, you're buying a genuine diamond, just one that was made above ground instead of mined from underground.

Why Do Lab Grown Diamonds Cost Less?

Lab grown diamonds cost 30% to 50% less than mined diamonds of the same quality. This isn't because they're lower quality. It's because of the supply chain.

Mined diamonds have a long, expensive journey from the earth to the retailer. Lab grown diamonds have a shorter, more efficient path. Fewer steps means lower costs, and those savings are passed on to you.

At Ecglosty, every lab grown diamond is IGI certified, and every piece is available in 14K or 18K white gold, yellow gold, rose gold, or platinum.

Do Lab Grown Diamonds Last?

Yes. Lab grown diamonds are permanent gemstones. They do not cloud, fade, or change color over time. They are just as durable as mined diamonds and are perfectly suited for everyday wear, including engagement rings.

A lab grown diamond will remain as brilliant decades from now as it was on the day you first wore it.

Final Thoughts

Lab grown diamonds are made using two main methods: CVD and HPHT. Both replicate the natural diamond-growing process and produce real diamonds that are chemically, physically, and optically identical to mined diamonds.

If you're looking for a lab grown diamond that's IGI certified and available in a full range of metals, browse our collection of lab grown diamond engagement rings and jewelry.

Information current as of October 2026.